About that list: as per usual in such lists written in the English language (US edition), what they mean is "100 Greatest American Screenwriters", with the odd foreigner thrown in. They also confess right at the start: It’s worth noting that Hollywood’s traditional exclusion of women and people of color makes it extraordinarily difficult to truly qualify the best in the craft, but acknowledging today’s urgent need for more inclusive storytelling doesn’t negate the contributions of these 100 pioneers.
That said, it's very satisfying to see pioneer Frances Marion (first scriptwriter, either male or female, to win the Oscar, twice) acknowledged at No.20), and the (imo deserved) number 1 spot goes to an immigrant to whom the English language was something he only learned as an adult (which turned out to be one of the all time successful love stories between a writer and an adopted language), the late, great Billy Wilder. Some of the other choices (even keeping the US pov in mind) are bewildering, no pun intended, but such is always the case.
In terms of Hollywood history, though, it amuses me that Joe Mankiewicz' brother Herman only makes it to No.56 while Orson Welles lands at No.41. Pauline Kael would roll in her grave. As the list writers themselves put it: Once upon a time, a small firestorm might have ignited over placing Orson Welles on a list of great screenwriters. For years, his co-authorship of Citizen Kane was in dispute, with many claiming that the credit belonged almost entirely to the great Herman J. Mankiewicz. (Pauline Kael even wrote an explosive, brilliant, deeply problematic essay arguing so, only for much of her research to be discredited later.) But even if he hadn’t co-written Citizen Kane (which he absolutely did), Welles would have been one of the great screenwriters of the 20th century. He was certainly one of the great adapters, able to take everything from the most acclaimed classics (think The Trial) to the lowest-brow pulp (think Touch of Evil) and make it his own. His Shakespeare adaptations are gems of concision and imagination, balancing respect for the text with a willingness to innovate. Look at the incredible Chimes at Midnight, where he takes pieces of several of the Bard’s plays and turns them into something completely modern.
I'm totally with them in terms of Orson as an adapter. (Which, btw, Welles biographer Simon Callow argues is what he did with Citizen Kane, too - Hermann Mankiewicz' original script - with some imput from John Houseman - was over three hours long, and Welles did what he did with Shakespeare, Kafka, and whoever wrote Touch of Evil - he cut, edited, added, rewrote, until the script had the shooting shape.) It's what makes his version of The Trial infinitely more interesting than the far more literal, bland and justly forgotten version of Kyle McLachlan as Joseph K. much later, and makes Chimes at Midnight show up later adaptions of the Henriad such as The Hollow Crown as deeply conventional and pulling their punches by comparison.
On a book-to-film note, thanks to chaila I've discovered Fall Equinox, a vid-athon wherein the vids in question are using book-based source material. I've only just started to watch my way through it, but check out Wherever I Go, a breathtaking exploration of the Gods in American Gods!