De Carle's Watch & Clock Encyclopedia (Third Edition)
Donald De Carle was the leading British horological author of the Post War period and this glorious publication first appeared in 1950. There have since been two updated editions and 14 printings in total of it.
It includes over 3,000 entries here on all aspects of watch and clock development and construction, all potentially of use to the horologist. But what I really like about this, as someone with a passing interest in clocks, and more in mechanics, is that it is virtually impossible to open one of this book's 330 pages, without finding fascinating things you didn't know before.
As a book to dip into it is wonderful for anyone, for the watch and clock maker it is indispensible. 1,400 illustrations - all drawings. Hardbound.