Viper,
The books you must read will greatly differ based on your experience and background.
As a military guy like yourself, one book that I *highly* suggest is: Everything Explained for the Professional Pilot (author - Richie Lengel). I've had it now for over a year. Definitely not a left to right, top to bottom type of book -- great scanning book with lots of "top off" GK that you haven't thought about since UPT.
Other threads I have read are from folks just polishing their 11-202V3 stuff, 11-217, etc.
From the guys who I have talked to in my SQ who are with the majors -- there is no reason to go all PhD on L/D Max when you already have all the skill sets the airlines are seeking. They hire personality just as much as aptitude. They mentioned the book I have as well as a current FAR/AIM….