The account book was used by Lancelot 'Capability' Brown between 1759 and 1783 to record staged payments received from clients and disbursements to sub-contractors, employees and nurseries. The volume is a working document, a standard 18th-century business ledger, with crosses drawn through entries to indicate when work was completed and an account paid in full. It has been suggested that the book is the only survivor of at least five used by Brown during his career. Some pages are signed 'L. Brown' and most of the entries appear to be in his hand. After Brown's death in 1783 entries were made by Samuel Lapidge, named in Brown's will as the successor to his business, who used the account book to record the completion of outstanding projects, settling the accounts and passing payment to Brown's executors.
The volume covers the years when Brown was at the peak of his career, with a client list including the King and members of the aristocracy. In the 1770s the account book shows that Brown was simultaneously masterminding projects at Blenheim, Burghley, Claremont, Luton, Sandbeck, Tottenham Park and Wimpole, as well as numerous smaller projects. Altogether the payments to Brown recorded in the volume total £320,000. Brown employed a team of surveyors, foremen, clerks of works, contractors and associates, who were responsible for much of what was delivered in Brown's name. Frequently mentioned in the account book are his surveyors John Spyers and Samuel Lapidge, his architectural partner (and son-in-law) Henry Holland and foremen Michael Mellican and William Ireland. These men oversaw the work of a large number of labourers and gardeners.
Brown's skills and knowledge were self-taught. Thanks to his early experience as a head gardener, Brown was a knowledgeable plantsman and there are hints of this in the account book in the form of references to his designing kitchen gardens, a task requiring technical and horticultural expertise. The volume includes payments to London nurseries for large numbers of trees and shrubs, as he used mature specimens to achieve immediate impact, inventing a tree-moving machine that used horsepower to transplant them. The account book records Brown's site visits, and his preference for travelling to southern properties in spring and to northern clients in the autumn.
The volume records a dispute in 1765 with Ambrose Dickens of Branches, Suffolk, over extra work worth £58 1s 8d. The entry reads, 'Mr Brown could not get the money for the Extra Work and tore the account before Mr Dickens face and said his say upon that Business to him.'