A plaine and easie introduction to practicall musicke, set down in forme ce a dialogue, devided into three partes, the first teacheth to sing with all things necessary for the knowledge of prickt-song. The second treateth of descante and to sing two parts in one upon a plainsong or ground, with other things necessary for a descanter. The third and last part entreateth of composition of three, foure, five or more parts with many profitable rules to that effect. With new songs of 2, 3, 4, and 5 parts