Original and useful ideas are infrequent in both economics and history. Most of us have to make do by appropriating from others and repackaging. But this book develops an idea that is both novel and ingenious. The author deserves much praise. The idea is to extract information on time use in Industrial Revolution England from witness statements in criminal trials. His central conclusion is that average hours of work for male workers increased by 30 percent between the 1750s and 1800, and by 20 percent between the 1750s and 1830. Indeed, his estimate of 3,500 hours per male worker in 1800 is the all-time high for England. Thus Voth finds evidence that the Industrious Revolution posited by Jan de Vries did accompany the Industrial Revolution. He concludes that even the meager productivity growth reported by Nick Crafts is still too high, since some increase in output was due to increased labor inputs. This reviewer has doubts, explained below, whether he has large enough samples of the appropriate types of workers to convincingly assert this central finding. But his method is correct in principle, and if extra data can be secured they will tell us a lot.