This book has a lot of very useful information on how to carry yourself in a professional studio as an Assistant Engineer. Some of the technical advice is a little... outdated(what is tape?). However, many of the same principles can still be made applicable in the digital realm, today. Overall, I find this book to still be pretty useful for budding Audio Engineers. Know your role, act professional, and you only need to get lucky once.
it's not the best reading material in the world as it stands, but it can help you survive through any session in any studio if you need the help. unlike "the mastering engineer's handbook", this is a true handbook.