Master metalsmith and teacher Tim McCreight wrote one of the bibles of metalsmithing, "The Complete Metalsmith" which has been revised many times over the years. I purchased the student version of the manual, hoping to get the basics on starting to do bench work. I was not disappointed!
McCreight covers every topic you'd want information on for starting bench work -- tools, techniques, materials. Be warned that this is NOT an instructional manual -- it is more of a dictionary that explains materials and techniques and how they pertain to metalwork. There are tips and hints and illustrations throughout of these techniques, but they do not explain projects from beginning to end. Despite the fact that it isn't an instruction manual, it is still an extremely useful guide to orientating yourself around a metalsmith workbench.
Spiral bound to lie flat and with heavy cardstock cover, this book is meant to be with you while you work. If you're just starting to explore metalsmithing, I recommend this book to help get you started. If you are craving more in-depth detail, consider getting the Professional Edition of this book.
The Complete Metalsmith, Student Edition on Amazon
The Complete Metalsmith, Professional Edition on Amazon
Tim McCreight's page on Amazon