This is a page from Robert O. Harder’s Air Navigation Manual (AF Manual 51-40).
The manual provides information on all phases of air navigation for navigators and students in training. Among many topics, it covers how to measure, map, and chart the earth; how to use basic instruments to obtain measurements; and how to solve basic navigation problem by dead reckoning and map reading.
This particular page covers radar mapping. In a note attached to the page, Harder stressed the importance of radar mapping and celestial navigation as keys to Strategic Air Command navigation.