Important sources of information about the early piano written in the 19th century include: The Pianoforte, its origin, progress and construction by Edward Rimbault 1860 and The History of the Pianoforte by Edgar Brimsmead 1879. Both these books are available to read online at www.archive.org. A description and history of the pianoforte and older keyboard stringed instrument by Alfred Hipkins 1896 is also a useful source of information. Publications in the early 20th century include; The Pianoforte by Rosamond Harding 1933, published by Hecksher and Co. 75 Bayham St, London and Early Keyboard Instruments by Philip James first published in 1930 but also reprinted in 1970.
Broadwood by Appointment written by David Wainwright, published in 1982, chronicles a definitive account of Broadwood from the early beginnings to recent time. (out-of-print) There are two more recent books by Michael Cole: The Pianoforte in the Classical Era published in 1995 by Clarenden Press Oxford (out-of-print) and Broadwood Square Pianos 2005 published by Tatchley Books, 334 Prestbury Road, Cheltenham. These two books have significantly added to our knowledge of the early piano. There have been academic papers published in the Early Piano magazine, Oxford Journals and the Galphin Society Journal.
A comprehensive account of piano makers and register of surviving instruments is given in: Makers of the Piano 1700-1820 published in 1993 and Makers of the Piano 1820-1860 published in 1999, both by Martha Clinkscale. This important work has been carried forward by John Watson of the Colonial Williamsburg Foundation in the United States in providing an online database version at www.earlypiano.org in which data entry can be made for instruments. Over 7000 instruments are currently included within the database.
An academic paper by Margaret Debenham and George Bozarth was published in the Royal Musical Association Research Chronicle No.42 (2009) entitled: Piano wars: The legal machinations of London pianoforte makers 1795-1806. This paper covers an in depth insight into the legal wrangles over piano patents associated with important technological development of the square piano at the beginning of the 19th century.
If you have an interest in rebuilding early pianos, we would recommend “The Handbook of Historical Stringing Practice for Keyboard Instruments” by Malcolm Rose and David Law, available from Malcolm Rose, The Workshop, English Passage, Lewes, East Sussex. This excellent publication provides examples of stringing specifications for early pianos and other keyboard instruments.
There are many other excellent books on the subject but it is not possible to give a comprehensive list in this article. Some of the publications above primarily cover the English piano. Out-of-print books may be obtained from your local library or may be available from second-hand book shops.