For really detailed tech/smithing info, Jerry Kuhnhausen's two shop manuals. For high-zoot competition types (might be a tad dated by now), Simpson's "The Custom Government Model." For general info, some smithing, Hallock's book on the .45. For the take from a guy in the business, Wilson's "The Combat Auto."
Note on Wilson: Yes, he pushes his stuff, but he also mentions some other brands and he does say that he thinks that extended slide releases and ambi safeties, including his own, are useless or worse on a carry gun.