The descriptions and illustrations are confined to the important and fundamental elements, so that time is not wasted reading a lot of useless or irrelevant detail. Readers are told plainly and briefly what each mechanism consists of, how it operates, and the features which make it of special interest. The particular mechanisms have been selected because they have stood the test of actual practice. Among the mechanisms described and illustrated by working diagrams are: cam applications and special cam designs, intermittent motions from gears and cams, interlocking devices, valve diagrams, reversing mechanisms of special design, tripping or stop mechanisms, drives of crank type for reciprocating driven members, feeding mechanisms and auxiliary devices, feeding and ejecting mechanisms, and many, many more.