Gee Whiz guys! How about a straight answer?!The flight manuals are based on extensive aviation research, history and flight testing. Go to them before you believe what somebody says here, the airport or even Wikipedia, the later which is actualy pretty good.When your experienced enough to know the difference you will start to understand when the SOPs manuals, checklists and Flight manuals don't cover what is happening right now in the aircraft or simply can't fix your problem at hand. No book or manual can cover all situations in the future but are typicaly based on thousands of hours of past experiences and the manufacturer's best SOPS for keeping you out of trouble, most of the time. Pilot judgement takes care of the rest, and we are alwyas learning...well most of us...