David Ricardo might have made the list as well. Tough to decide on only 100, actually - you have to leave out some whose influence was derivative, through other books, and include some that have a notoriety disproportionate to their actual influence - I'd place Mao's Little Red Book under that category. I have a copy (bought in Kowloon during the bad old days) and frankly, it's trite, silly, and could be said to influence anything because it seems to say almost anything.
I have something of a soft spot for books that weren't even translated into English until very late - The Thousand Nights And One Night for example. Sir Richard Burton's wife actually burnt his original translations for obscenity... She was cursed as a thoughtless Victorian prude until somebody figured out just how obscene they really were...