This book is a definite must read for anyone considering army life. It walks you through exactly what the military expects from its soldiers in the army. From training, personal morals, its history, customs, traditions... well, you get the idea and I don't really want to sound like the table of contents here. However, that said (and bearing in mind at the time of my review there were only 2 real options for purchasing a hard copy of this guide: 1 new for nearly $1000; 1 used for around $40), this publication is "approved for public release; distribution is unlimited."
Simply hop to your favorite search engine and look up FM 7-21.13 "THE SOLDIER'S GUIDE". However, if a copy becomes reasonably priced, I would buy it. It was a much better reading experience having the book in my hands than the re-read I did from the internet, but, any port in a storm.