Mainly a mechanism is built to generate certain trajectories or to obtain a certain correlation between the output motion and the input motion (i.e. a transfer function). Obviously, there are different situations when mechanisms are needed in certain particular cases. This book analyzes the transfer functions generated by numerous planar mechanisms, starting from the trajectories generated by certain points of these mechanisms. An original method of establishing transfer functions was developed by completing the trajectory generating mechanism with an additional kinematic chain (a dyad). The designer will look for the desired function between these races, given in diagrams, or will look for other mechanisms, the book being also an at-las of transfer functions.