This book comprises two parts: a discussion of about 100 pages on the origins and growth of the London trade in scientific instrument making between 1540 and 1610, and on its main protagonists, serving as an introduction to a catalogue raisonné (c. 200 pages) of all recorded instruments by Elizabethan makers, including unsigned ones. For the latter the author wisely inserted an appendix (“The Attribution of Unsigned Instruments”) explaining a script-based methodology for making attributions of unsigned pieces. Comparative tables of letters and numbers from signed and unsigned instruments are put side-by-side, providing a more or less scientific foundation for an otherwise subjective exercise.