This is a great book and I loved it even though it was written in 1963. It's about then-current research into methods for breeding the best-possible guide dogs. It's mainly about methods used at GDB, although TSE is also mentioned a few times, and the studies done at Jackson Laboratory in Maine. Breeding is largely a mystery to me and even though this book is old, it helped me to understand more about breeding than any of the numerous contemporary sources I've looked at.
Besides being useful, it is also, of course, a pretty amazing look into the guide dog world more than 50 years in the past. For a guide dog nerd like me, that is heaven. Sure, some things were different, but I was also struck by how many things were the same.
Note to self: find out the answer to the question of why we don't do puppy tests anymore? Did they stop having predictive value, did they become logistically impossible or what?
If you haven't read this book and you think you are a serious dog trainer, breeder, handler, helper or anything to do with dogs then you should. It all starts here.