Amazon Safe Opening Books
Priced around $174.00 its an expensive kindle book but it may be worth it to you for what you get.
Any one can buy it unlike those books sold to "only locksmiths".
I believe that printing is enabled in this book for when you want a hard copy of the info when you go out on a call.
You can also see what you are buying (lots of photos of safe innards and drill points by accessing the free first few chapters.
Amazon kindle lets you buy it, have a good look at it to see if you want it, and either keep it or return it for an easy refund.
In other words money back if you are not happy with it.
This free peek at a few chapters lets you see the quality of the photos (pretty good in my opinion) by clicking on this link.
https://www.amazon.ca/Guide-Opening-Free-Standing-Safes-ebook/dp/B01HQNP91S/ref=sr_1_3?ie=UTF8&qid=1514502978&sr=8-3&keywords=opening+safes#reader_B01HQNP91S
Whether for the locksmith wishing to advance into the world of safe opening or for the layman who is curious about the history and workings of old and modern safes this is the book for you. This book will assist you in identifying and opening a huge variety of free standing safes with hundreds of pictures, measurements and drill points for assistance. More importantly it will give you the expertise, knowledge and competence to make money in the exciting and lucrative world of safe opening.
The 2nd book is Safecracking by Franklin. About $10.00
Has photos of open safe lock and an explanation of how to read the numbers.
https://www.amazon.ca/Safecracking-Manipulating-Mechanical-Combination-Locks-ebook/dp/B013Z5FMSQ/ref=sr_1_2?ie=UTF8&qid=1514505378&sr=8-2&keywords=safecracking