NEARLY thirty years ago, I published a book about the evolution of English organ design between 1820 and 1870. The present work broadens the time span to cover the period from 1770 to 1890, but narrows its focus to the activities of one particular firm of organ-builders: Gray (later Gray & Davison), who made organs in Holborn, St Pancras and Pentonville in London over the course of nearly two hundred years until the business closed around 1970.

The firm's history is significant for a number of reasons. First, it illustrates the evolution of a typical instrument-making workshop of the mid-Georgian period into a Victorian organ factory. Secondly, from the 1790s until the 1880s the firm was one of the country's leading organ-makers and was responsible for important musical and mechanical innovations, especially in the design of concert organs. Thirdly, the history of the firm is well served by surviving documentation: the ledgers are complete from 1821, the shop books from 1840, and there are also some working drawings. In addition to a chronology of the firm's work, these sources cast light on business and workshop practices, profitability, clients, staff and premises, as well as reflecting changes in musical taste and liturgical use, collaboration with organists, clergy and architects, and innovations in console design and casework.

It has always been the author's intention to make this a documentary history of its subject. This necessarily limits its scope. Cultural context and musical use are discussed at some length, but comparatively little technical information has been included. Those wishing to learn more of such matters should consult the pioneering work of David Wickens, who has measured and analysed pipe scales and recorded pipe markings, and David Frostick's dissertation on nineteenth-century reed voicing, with detailed examination of the work of Gray & Davison. Also, Goetze & Gwynn have restored a number of Gray chamber organs in recent years, and restoration reports including photographs and technical data are available online.

Today, a majority of the instruments made by the Grays and Gray & Davison have been lost or altered out of all recognition: the firm's magnum opus for Leeds Town Hall (1859), for instance, was comprehensively rebuilt only forty years after its installation as a consequence of changing musical fashion.