A cam produces any prescribed motion of its follower. The follower types (knife edge, roller, flat face, translating or oscillating), the motion laws and their displacement, velocity, acceleration and jerk, and why a cam must have continuous acceleration at high speed. The pressure angle, the cam analogue of the transmission angle, and the base circle that keeps it small. The cam profile from the follower motion, generated in Python and printed. Examples: the valve train of an engine, the cam of a mechanical timer, the cam latches of Over-centre mechanisms, and the printed examples of Figure 11.10.1: a locking latch, an indexing dial, a dispenser that releases one item per turn, and an automaton driven by several cams on one shaft. Each is checked by hand and in the motion solver of Simulating mechanisms in Python, with contact between cam and follower.