I collect books which claim to contain The Best 100/1000 of film, so believe me when I tell you that this is a good one. Created by the people who did 1001 Movies You Must See Before You Die (which I own and have reviewed), this version avoids many of the problems that claim the bigger version:
Unlike 1001 Movies, this one does not only appeal to cineastes. Instead of seemingly including every foreign film that was ever made regardless of quality, it strikes a balanced chord between American and international pictures. It also has an appropriate ratio of edgier artistic films (2001: A Space Odyssey, La Jetee, Alphaville, etc.) and mainstream successes (Star Wars IV-VI, Independence Day, Them!) without condescending to the latter.
Artistically and aesthetically the book is also a success. Each film gets the same amount of space (one of the problems with 1001 movies was that some films got 2 pages worth and others a paragraph or two) as well as a beautiful color poster and screenshot, making it not only informative but really quite pleasant to look at. The different authors use radically different tones (from intellectual discussion of reactionary vs. progressive to less scholarly examination of riveting chase scenes) which can be jarring at times, but it always makes for interesting reading, whether you agree or not.
The people who wrote this book clearly love movies (something that oddly cannot be said for all such works) and mainly avoid the lazy errors that often plague the genre. My only real complaint is I wish they had listed the running length of each film, but that's hardly a major concern. Basically, for 10 dollars you get a beautiful, full color illustrated (I actually washed my hands before reading it to avoid smudges, and I'm not a fastidious person) well-written treatise on 100 great Sci-fi movies from Voyage to the Moon to Children of Men, and that's really quite a good deal. You won't agree with or have seen all 100, but then again it would be quite a boring book if you had.