"THIS book is the sequel to a very much larger work, a five-volume History of Technology, endowed by Imperial Chemical Industries Limited and published by the Clarendon Press, Oxford. When the compilation of this large work was approved in 1949 it was expected that there might in due course be a demand for a smaller book covering much the same ground. This expectation has been fulfilled: many reviewers of the earlier volumes specifically urged the publica- tion of a shorter version that would introduce the subject to a much wider body of readers. In view of this, I.C.I. agreed to make avail- able the further endowment that was necessary and the Clarendon Press undertook publication: the present book is the result."