The first and largest section is concerned with design of the-array excitation: the set of complex numbers representing drive currents or voltages. Narrow-beam and shaped-beam design principles are covered in detail for uniformly spaced arrays, followed by constrained synthesis. The important topic of superdirectivity (super gain) is treated in depth. Non-uniformly spaced (thinned) arrays, and array tolerances are also treated. Section 2 covers array feeds: resonant (standing wave), travelling wave, corporate, line and distributed. Salient lobes produced by phaser quantisation or by sub-arraying are then studied. In Section 3 array elements are the topic, primarily low gain elements such as slots, dipoles, microstrip elements etc. Moderate gain elements such as spirals, log-periodics, horns etc. are covered in other chapters.