I could be wrong on this, but since there is not a main 'governing' body for poker, there probably is no "official rule book". With baseball, you also probably have to get a MLB, NCAA... rule book. Football: NFL, NCAA... Racing: NASCAR... In games/sports there are technically no official rules, unless under a particular governing body. The closest you could come would be to find a WSOP
or WPT rule book. Even then they are usually just rules regarding tournies. Roberts Rules will be the closest you will come to "official" rules. I'm not asking this to be rude, it's and honest thought to your question; who would create the rule book you are looking for? The answer to that would more than likely be no one in particular, and the second answer may be WSOP or WPT or which ever governing body is controlling where you play poker i.e. a hotel/casino/bar.
Someone please correct me if I'm wrong.