This is the second selection of articles by Rupert Hall to be published by Variorum. Whereas the first volume focused on Newton and his work, the present one ranges more widely over the interactions between ‘pure’ science, ‘applied’ science, and craftsmanship, but with an emphasis on the period from the 17th century to the Industrial Revolution. The second and third sections look in particular at the relations between science and warfare, and science and medicine, and the position of the Royal Society forms the focus of several papers. Throughout Professor Hall argues for the need to keep in mind that the distinction between the practical or professional and the intellectual was not then valid in the same way as now; that the problems of the interaction and interdependence between ‘knowing’ and ‘doing’ are not invariant, but rather historically determined and with defined historical contexts.