Although modern etymologists would question Burney's appropriation of a Greek word with a general meaning (organon seems to have meant a tool with which to do a job of work) for so specific a purpose, it would be hard to deny that the pipe organ in its most developed form is structurally the largest, and (for sheer variety of effect) musically the most comprehensive of all instruments. And if by ‘harmonious’ is meant the capacity to order diverse elements and bring them into concord with one another for a common purpose, then Burney's claim for the organ, with its multiplicity of sound-producing and mechanical parts, can surely be substantiated.

At its most basic, the organ is a simple wind instrument. It consists of a grooved chest supporting a set of pipes, bellows to supply wind to the pipes, and some sort of mechanism to cause the pipes to sound. Though such simplicity is now rare it perfectly well describes the sort of organ depicted in medieval illuminated manuscripts (Figure 1.1). The path from such modest instruments to giant modern organs boasting four or five keyboards, 32 pipes, dozens of registers, sophisticated stop controls and electrical blowing apparatus encompasses a complex and fascinating process of development in which music, technology, architecture, liturgy, industrial organisation and changing taste all play a part.