David Letterman and Jay Leno's late night rivalry detailed in explosive new book

In his new biography, "Letterman: The Last Giant of Late Night," author Jason Zinoman details the infamous late night rivalry between David Letterman and Jay Leno throughout the '90s and '00s.

In excerpts obtained by People, Zinoman details how Leno was able to snag the gig as host of "The Tonight Show" in 1991 upon Johnny Carson's retirement over Letterman, and Letterman's subsequent reaction to the news.

SEE ALSO: Jay Leno returns to 'Tonight Show,' takes on Trump and Clintons in monologue

"Letterman assumed one day he would get a call from Carson or the head of NBC to offer him the job. It never happened," Zinoman revealed in his book. "Rick Ludwin, head of late-night programming at NBC, respected Letterman as a great entertainer but was skeptical that he could draw the broad swath of viewers that made up the 'Tonight Show' audience."

Not only that, but Ludwin "also saw Letterman as difficult to deal with. Whereas Leno was friendly and approachable, Letterman was distant, even hostile."

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David Letterman's fashion over the years
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THE TONIGHT SHOW STARRING JOHNNY CARSON -- Pictured: Guest host David Letterman on March 26, 1979 -- Photo by: Paul Drinkwater/NBC/NBCU Photo Bank
LOS ANGELES - FEBRUARY 8: MORK AND MINDY. David Letterman as Ellsworth in ' Mork goes Erk'. Original airdate February 8, 1979. Image is a screen grab. (Photo by CBS via Getty Images)
THE DAVID LETTERMAN SHOW -- Season 1 -- Pictured: (l-r) -- Host David Letterman, cast/writers Edie McClurg, Valri Bromfield, Gerard Mulligan (Photo by: NBC/NBCU Photo Bank via Getty Images)
THE DAVID LETTERMAN SHOW -- Pictured: Host David Letterman with guests -- (Photo by: NBC/NBCU Photo Bank via Getty Images)
THE DAVID LETTERMAN SHOW -- Season 1 -- Pictured: (l-r) -- Host David Letterman in Shubert Alley (Photo by: NBC/NBCU Photo Bank via Getty Images)
David Letterman during 39th Annual Emmy Awards - September 20, 1987 at Pasadena Civic Auditorium in Pasadena, California, United States. (Photo by Jim Smeal/WireImage)
David Letterman during The 37th Annual Emmy Awards at Pasadena Civic Auditorium in Pasadena, CA, United States. (Photo by Ron Galella/WireImage)
LOS ANGELES - CIRCA 1983: Host David Letterman poses for a portrait in c.1983 in Los Angeles, California. (Photo by Donaldson Collection/Michael Ochs Archives/Getty Images)
UNITED STATES - APRIL 19: NBC Newsman Edwin Newman and David Letterman on the David Letterman show. (Photo by The LIFE Picture Collection/Getty Images)
UNITED STATES - APRIL 01: Jerry Garcia, Bob Weir, and David Letterman (Photo by The LIFE Picture Collection/Getty Images)
THE TONIGHT SHOW STARRING JOHNNY CARSON -- Pictured: Guest host David Letterman on March 26, 1979 -- Photo by: Paul Drinkwater/NBC/NBCU Photo Bank
UNITED STATES - APRIL 01: David Letterman with Jerry Garcia and Bob Weir (Photo by The LIFE Picture Collection/Getty Images)
NEW YORK - JULY 7: Headshot of David Letterman for the show, 'Mary.' Image dated July 7, 1978. (Photo by CBS via Getty Images)
NEW YORK - FEBRUARY 26: Comedian Joan Rivers shares a laugh with Dave when she visits the Late Show with David Letterman Tuesday Feb. 26, 2013 on the CBS Television Network. (Photo by Jeffrey R. Staab/CBS via Getty Images)
LATE NIGHT WITH DAVID LETTERMAN -- Pictured: (l-r) Comedian Jay Leno, host David Letterman -- (Photo by: NBC/NBCU Photo Bank via Getty Images)
Portrait of American talk show host David Letterman smiling at his home, Westchester County, New York, March 1984. (Photo by Susan Wood/Getty Images)
UNITED STATES - APRIL 01: David Letterman (Photo by The LIFE Picture Collection/Getty Images)
THE DAVID LETTERMAN SHOW -- Season 1 -- Pictured: (l-r) -- Host David Letterman (Photo by: NBC/NBCU Photo Bank via Getty Images)
THE DAVID LETTERMAN SHOW -- Episode 36 -- Pictured: (l-r) President Jimmy Carter's son James 'Chip' Carter, host David Letterman on August 11, 1980 -- (Photo by: NBC/NBCU Photo Bank via Getty Images)
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In response to the snub, Letterman "decided that [he] didn't like [NBC president] Warren Littlefield because [he] didn't get 'The Tonight Show.'"

"I blamed the whole thing on him, rather than taking responsibility for myself," Letterman admitted.

Zinoman wrote in "The Last Giant of Late Night" that this kind of anger wasn't uncommon coming from Letterman. In fact, it was more normal than not for him to be unhappy with someone or something.

"Everyone is born with an emotional thermostat," writer Steve Young told Zinoman. "You can nudge it up and down, but it will always revert to its natural setting. His was that he was never truly comfortable unless he was seething with unhappiness at something."

"Letterman: The Last Giant of Late Night" by Jason Zinoman hit bookshelves on April 11.

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Jay Leno through the years
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WASHINGTON, DC - OCTOBER 19: Honoree Jay Leno poses for a photo with fans at the 2014 Kennedy Center's Mark Twain Prize For American Humor honoring Jay Leno at The Kennedy Center on October 19, 2014 in Washington, DC. (Photo by Paul Morigi/WireImage)
WASHINGTON, DC - OCTOBER 19: (L to R) Alex Sykes, Wanda Sykes, honoree Jay Leno and his wife Mavis arrive at the 2014 Kennedy Center's Mark Twain Prize For American Humor honoring Jay Leno at The Kennedy Center on October 19, 2014 in Washington, DC. (Photo by Paul Morigi/WireImage)
WASHINGTON, DC - OCTOBER 19: Honoree Jay Leno arrives at the 2014 Kennedy Center's Mark Twain Prize For American Humor honoring Jay Leno at The Kennedy Center on October 19, 2014 in Washington, DC. (Photo by Paul Morigi/WireImage)
WASHINGTON, DC - OCTOBER 19: Honoree Jay Leno and his wife Mavis Leno arrive at the 2014 Kennedy Center's Mark Twain Prize For American Humor honoring Jay Leno at The Kennedy Center on October 19, 2014 in Washington, DC. (Photo by Paul Morigi/WireImage)
WASHINGTON, DC - OCTOBER 19: Honoree Jay Leno arrives at the 2014 Kennedy Center's Mark Twain Prize For American Humor honoring Jay Leno at The Kennedy Center on October 19, 2014 in Washington, DC. (Photo by Paul Morigi/WireImage)
WASHINGTON, DC - OCTOBER 19: Honoree Jay Leno arrives at the 2014 Kennedy Center's Mark Twain Prize For American Humor honoring Jay Leno at The Kennedy Center on October 19, 2014 in Washington, DC. (Photo by Paul Morigi/WireImage)
BEVERLY HILLS, CA - OCTOBER 11: Master of Ceremonies Jay Leno speaks onstage at the 2014 Carousel of Hope Ball presented by Mercedes-Benz at The Beverly Hilton Hotel on October 11, 2014 in Beverly Hills, California. (Photo by Kevin Winter/Getty Images)
BEVERLY HILLS, CA - OCTOBER 11: Recording artist Josh Groban (L) and master of ceremonies Jay Leno speak onstage at the 2014 Carousel of Hope Ball presented by Mercedes-Benz at The Beverly Hilton Hotel on October 11, 2014 in Beverly Hills, California. (Photo by Kevin Winter/Getty Images)
BEVERLY HILLS, CA - OCTOBER 11: Master of Ceremonies Jay Leno (L) and music producer David Foster speak onstage at the 2014 Carousel of Hope Ball presented by Mercedes-Benz at The Beverly Hilton Hotel on October 11, 2014 in Beverly Hills, California. (Photo by Kevin Winter/Getty Images)
BEVERLY HILLS, CA - OCTOBER 11: Master of Ceremonies Jay Leno (L) and Carousel of Hope Chairman Barbara Davis speak onstage at the 2014 Carousel of Hope Ball presented by Mercedes-Benz at The Beverly Hilton Hotel on October 11, 2014 in Beverly Hills, California. (Photo by Kevin Winter/Getty Images)
BEVERLY HILLS, CA - OCTOBER 11: Jay Leno and wife Mavis Leno arrive at the 2014 Carousel Of Hope Ball Presented By Mercedes-Benz at The Beverly Hilton Hotel on October 11, 2014 in Beverly Hills, California. (Photo by Gregg DeGuire/WireImage)
BEVERLY HILLS, CA - OCTOBER 11: Comedian Jay Leno attends the 2014 Carousel of Hope Ball at The Beverly Hilton Hotel on October 11, 2014 in Beverly Hills, California. (Photo by Jason LaVeris/FilmMagic)
BURBANK, CA - SEPTEMBER 24: Jay Leno poses for a portrait at his car garage on Wenesday September 24, 2014 in Burbank, CA. The longtime host of The Tonight Show, continues to tour extensively performing comedy. Leno is going to be the next recipient of the Mark Twain Prize for American Humor. (Photo by Matt McClain/ The Washington Post via Getty Images)
BURBANK, CA - SEPTEMBER 24: Jay Leno is interviewed at his car garage on Wenesday September 24, 2014 in Burbank, CA. The longtime host of The Tonight Show, continues to tour extensively performing comedy. Leno is going to be the next recipient of the Mark Twain Prize for American Humor. (Photo by Matt McClain/ The Washington Post via Getty Images)
LANCASTER, PA - SEPTEMBER 21: Jay Leno changes clothes after performing at the American Music Theatre on Sunday September 21, 2014 in Lancaster, PA. The longtime host of The Tonight Show, continues to tour extensively performing comedy. Leno is going to be the next recipient of the Mark Twain Prize for American Humor. (Photo by Matt McClain/ The Washington Post via Getty Images)
LANCASTER, PA - SEPTEMBER 21: Jay Leno performs at the American Music Theatre on Sunday September 21, 2014 in Lancaster, PA. The longtime host of The Tonight Show, continues to tour extensively performing comedy. Leno is going to be the next recipient of the Mark Twain Prize for American Humor. (Photo by Matt McClain/ The Washington Post via Getty Images)
LANCASTER, PA - SEPTEMBER 21: Jay Leno is interviewed before performing at the American Music Theatre on Sunday September 21, 2014 in Lancaster, PA. The longtime host of The Tonight Show, continues to tour extensively performing comedy. Leno is going to be the next recipient of the Mark Twain Prize for American Humor. (Photo by Matt McClain/ The Washington Post via Getty Images)
THE TONIGHT SHOW WITH JAY LENO -- Episode 4610 -- Pictured: Host Jay Leno reminisces on his 22 year run as host of the Tonight Show on February 6, 2014. (Photo by: Chris Haston/NBC/NBCU Photo Bank via Getty Images)
THE TONIGHT SHOW WITH JAY LENO -- Episode 4610 -- Pictured: (l-r) Actor Jack Black, host Jay Leno and Kim Kardashian during Jay Leno's farewell song on February 6, 2014. (Photo by: Stacie McChesney/NBC/NBCU Photo Bank via Getty Images)
THE TONIGHT SHOW WITH JAY LENO -- Episode 4610 -- Pictured: (l-r) Actress Carol Burnett, singer Sheryl Crow, actor Jack Black, basketball player Chris Paul, host Jay Leno, actor Jim Parsons, Kim Kardashian, and Oprah Winfrey during Jay Leno's 'Farewell Song' on February 6, 2014. (Photo by: Stacie McChesney/NBC/NBCU Photo Bank via Getty Images)
THE TONIGHT SHOW WITH JAY LENO -- Episode 4610 -- Pictured: (l-r) Musical guest Garth Brooks and host Jay Leno on February 6, 2014. (Photo by: Chris Haston/NBC/NBCU Photo Bank via Getty Images)
THE TONIGHT SHOW WITH JAY LENO -- Episode 4610 -- Pictured: Musical guest Garth Brooks performs on February 6, 2014. (Photo by: Stacie McChesney/NBC/NBCU Photo Bank via Getty Images)
BURBANK, CA - FEBRUARY 06: Comedian Jay Leno appears onstage during a commercial break on the final episode of "The Tonight Show with Jay Leno" at The Burbank Studios on February 6, 2014 in Burbank, California. (Photo by Kevin Winter/Getty Images)
THE TONIGHT SHOW STARRING JOHNNY CARSON -- Air Date 01/28/1992 -- Pictured: Guest host Jay Leno on January 28, 1992 (Photo by Joseph Del Valle/NBC/NBCU Photo Bank via Getty Images)
THE TONIGHT SHOW WITH JAY LENO -- Episode 30 -- Pictured: host Jay Leno during 'presidential poll' segment on June 30, 1992 (pictured) president William (Bill) Jefferson Clinton (Photo by Wendy Perl/NBC/NBCU Photo Bank via Getty Images)
BURBANK, CA - AUGUST 4: Senator Hillary Rodham Clinton appears on the 'Tonight Show with Jay Leno' at the NBC Studios August 4, 2003 in Burbank, California. (Photo by Kevin Winter/Getty Images)
THE TONIGHT SHOW WITH JAY LENO -- Episode 4570 -- Pictured: (l-r) Former President George W. Bush during an interview with host Jay Leno on November 19, 2013 -- (Photo by: Stacie McChesney/NBC/NBCU Photo Bank via Getty Images)
Al Gore at 'The Tonight Show with Jay Leno' at the NBC Studios in Burbank, Ca. Wednesday, Nov. 27, 2002. Photo by Kevin Winter/ImageDirect.
LATE NIGHT WITH DAVID LETTERMAN -- Episode 1144 -- Pictured: (l-r) The new host of 'The Tonight Show' Jay Leno, host David Letterman on May 7, 1992 -- (Photo by: NBC/NBCU Photo Bank via Getty Images)
Comedian Jay Leno during an interview with guest host David Letterman on July 4, 1979. (Photo by Paul Drinkwater/NBCU Photo Bank)
Jay Leno arrives on May 5, 2014 for a demonstration in support of Women's Rights and LGBT groups across from the Beverly Hills Hotel, owned by the Sultan of Brunei, who also owns the Bel-Air Hotel in Los Angeles, in Beverly Hills, California, which passed a resolution demanding May 7, 2014 the Sultan of Brunei, Hassanal Bolkiah, sell his hotel in the posh US city after he announced last week that he would push ahead with implementing sharia law, despite criticism both at home and internationally. The city council said they will send the resolution to the State Department asking Washington to 'take appropriate action to condemn the Brunei government's policies.' AFP PHOTO / Frederic J. BROWN (Photo credit should read FREDERIC J. BROWN/AFP/Getty Images)
BEVERLY HILLS, CA - MAY 5: Comedian Jay Leno participates in a rally to protest draconian punishment of women and gay people announced by the Sultan of Brunei outside the Beverly Hills Hotel, which is owned by the Sultan, on May 5, 2014 in Beverly Hills, California. The Sultan of Brunei is planning to implement a brand of Sharia Penal Code which calls for the stoning of people for various offenses including homosexual acts, adultery, sodomy and extramarital sexual relations, a move that has been criticized by The United Nations. (Photo by David McNew/Getty Images)
BEVERLY HILLS, CA - MAY 5: Comedian Jay Leno participates in a rally to protest draconian punishment of women and gay people announced by the Sultan of Brunei outside the Beverly Hills Hotel, which is owned by the Sultan, on May 5, 2014 in Beverly Hills, California. The Sultan of Brunei is planning to implement a brand of Sharia Penal Code which calls for the stoning of people for various offenses including homosexual acts, adultery, sodomy and extramarital sexual relations, a move that has been criticized by The United Nations. (Photo by David McNew/Getty Images)
BEVERLY HILLS, CA - MAY 5: Comedian Jay Leno participates in a rally to protest draconian punishment of women and gay people announced by the Sultan of Brunei outside the Beverly Hills Hotel, which is owned by the Sultan, on May 5, 2014 in Beverly Hills, California. The Sultan of Brunei is planning to implement a brand of Sharia Penal Code which calls for the stoning of people for various offenses including homosexual acts, adultery, sodomy and extramarital sexual relations, a move that has been criticized by The United Nations. (Photo by David McNew/Getty Images)
BEVERLY HILLS, CA - MAY 5: Comedian Jay Leno participates in a rally to protest draconian punishment of women and gay people announced by the Sultan of Brunei outside the Beverly Hills Hotel, which is owned by the Sultan, on May 5, 2014 in Beverly Hills, California. The Sultan of Brunei is planning to implement a brand of Sharia Penal Code which calls for the stoning of people for various offenses including homosexual acts, adultery, sodomy and extramarital sexual relations, a move that has been criticized by The United Nations. (Photo by David McNew/Getty Images)
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