"Speed Control Line Models" is a hardcover book written by Ron Warring of England and published in 1949 by Percival Marshall. It represents a fascinating and quite comprehensive survey of the early development of control line speed models both in Britain and in the USA up to 1949. Although only one chapter is devoted exclusively to engines (with another chapter discussing jets), it remains a work of considerable interest to those interested in the development of control line speed models from their earliest beginnings. 

The book understandably became dated relatively quickly following its initial publication, hence not remaining in print for very long.  As a result, it is not exactly common today, but copies in reasonable condition do show up from time to time on eBay and elsewhere. Well worth a look ..............