The Novelization of Once Upon a Time in Hollywood (OUTH) is fundamentally the same story as the film; it's just told differently. There are chapters that play almost identically to the film, some that expand on what's there, portions that are completely new, and finally, things left out completely - probably for the better. Typical of Quintin Tarantino, what you do get is told in an order unique from the film.
The major details all remain the same with the Manson Family, 1960s Film and Television production, and the sputtering career of Rick Dalton (and all of his feelings of self loathing and inadequacy) being the focus. Sharon Tate's fictionalized version is given the same amount of attention, with slightly more to be said about her relationship with Polanski.
The Cliff Booth character remains the most interesting and enigmatic, and as with the film, the best parts of the book tend to be all about him. The controversial Bruce Lee scene won't solve any of the problems people had with the film version, but it still remains an exciting fictionalization of the martial arts legend, in my opinion.
The lesson Tarantino seems to want his reader to take from the book is to recognize the good times when you're in them. For the author, that goes for Dalton, the Lancer actor James Stacey (whom would have his life
change forever in reality a few years later), the Polanskis, and 1960s Hollywood. If something doesn't seem rotten, it probably is, and if it isn't, it will become rotten soon enough.
Tragedy, seemingly, is always around the corner, and while the Polanskis were spared their own destiny, the same is certainly not true for Stacey, who's fate in the book never changes, and interestingly, would walk a similar path to Polanski's.
And while I'd like to think otherwise, this book also makes no guarantees of happiness and fulfilment for the heroic, aging, misfit duo, Rick Dalton and Cliff Booth. They probably go on living just the way they always have and they themselves, through their own choices, will suffer from the same rot that seems to have taken a hold of everything else in this story.