James Watt was granted his first patent on a steam engine in 1769, but he ran into financial difficulties in trying to exploit it. Fortunately, he was to find a solid businessman—Matthew Boulton—to handle the finances and marketing. In 1775, the firm of Boulton & Watt was established and obtained a twenty-five-year extension of Watt's patent. Watt's inventive genius and Boulton's keen eye for new markets and applications was a successful combination, and their engines were a prime power source for the first Industrial Revolution. The company's papers, and the personal papers of the founders, are preserved in Birmingham, England, and are a unique source of information and insight regarding the emergence of the modern technological era. The most significant and revealing of these papers will be systematically edited and published in a series of volumes, of which this is the first. Some eight years of research have already been invested in this mammoth project, and the rewards should be substantial for historians, whether their interests center on science and technology, business and industrial development, or social and economic change. The 213 documents in volume 1 trace the emergence of the partnership, describe the state of engine technology, cover the firm's patents and privileges at home and abroad and its difficulties with pirates, spies, and competitors, and reflect the development of the engine business: separate sections deal with subcontracting practices, customer complaints, profits and premiums, engineers and mechanics, the Soho foundry and engine manufactory, and engine sales (and after-sales service) in both the domestic and overseas markets.