Practical Course in Modern Locksmithing, Whitcomb Crichton, Copyright 1943 - 1971, 222 pages 6" X 9", no ISBN.
This book shows up used on Amazon every now and then for a few dollars. On the title page it notes that it is "A Benj. Franklin Home-Study Course Complete in One Volume." That sounds promising. A 40+ year old book is obviously dated, but some elements of locksmithing have not changed since then.
Contents:
1. Introduction to the Trade - glossary of terms, how doors are handed, etc.
2. Tools and Equipment.
3. Warded Locks - a page on how to fit keys.
4. Lever Locks - several pages on fitting keys and service.
5. Disc Tumbler Locks - briefly goes over disc tumbler, the Schalge wafer tumbler locks, and mentions a short-lived crushable self-keying disc lock.
6. Pin Tumbler Locks - discusses pinning locks, suggests filing down pins (common back then).
7. Masterkeying - really likes Corbin with all their different key ways, so each floor of a building can have a different key way. Does not really go into how to actually masterkey.
8. Service Hints - mentions Best SFIC, cutting keys by code, etc. Mention being the operable word.
9. Safes- discusses how to change combinations, how they operate, etc.
What the book is obviously lacking in is anything to do with picking, impressioning, or bypassing. It was also strangely lacking in automotive locksmithing, back when a locksmith could just about do anything that needed doing to a car with minimal tools. The page count was 222, but the lower margin is about 1 1/2" so it is really smaller than it seems.
Overall, there is nothing very useful in the book, not now and probably not then either. What was discussed tended to be at a high level. More like a long pamphlet to be handed out by high-school career counselors. It is of interest possibly as "locksmith lore", a look back on what the trade used to be. For example, there is a suggested list of hand tools, to take on service calls in something like a doctor's bag, and the writer reminisces about carrying the tool kit to service calls via streetcar.
Of all the books I have seen this is probably the one with the least to offer.