A new book providing the ultimate behind-the-scenes look at The Big Bang Theory's twelve-year run was released today. The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series is a 528-page oral history of the show based on over 120 hours of interviews with the cast, creators and producers of The Big Bang Theory.

Written by Jessica Radloff, a senior editor at Glamour who covered the show during its time on air and even made a cameo appearance in the series finale, the book was released to mark the fifteenth anniversary of The Big Bang Theory's premiere.

THE BIG BANG THEORY: THE DEFINITIVE, INSIDE STORY OF THE EPIC HIT SERIES is a riveting, entertaining look at the sitcom sensation, with the blessing and participation of co-creator Chuck Lorre and Bill Prady, executive producer Steve Molaro and Steve Holland, as well as Johnny Galecki, Jim Parsons, Kaley Cuoco, Simon Helberg, Kunal Nayyar, Melissa Rauch, Mayim Bialik, and more. Glamour senior editor Jessica Radloff, who has written over 150 articles on the series (and even had a cameo in the finale!), gives readers an all-access pass to its intrepid producing and writing team and beloved cast. It’s a story of on-and-off screen romance told in hilarious and emotional detail, of casting choices that nearly changed everything (which even some of the actors didn’t know until now), of cast members bravely powering through personal tragedies, and when it came time to announce the 12th season would be its last, the complicated reasons why it was more difficult than anyone ever led on. Through hundreds of hours of interviews with the sitcom’s major players, Radloff dives into all this and much more. The book is the ultimate celebration of this once-in-a-generation show and a must-have for all fans.

Check out excerpts from the book about Johnny Galecki and Kaley Cuoco's real-life romance, the other actresses originally cast in the "Penny" role, and Kaley Cuoco's Season 8 hairstyle.

Buy The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series from Amazon.com