There are two justifications for a new edition of D'Arcy Wentworth Thompson's On Growth and Form: One is that a shorter version might make the work more available, at least to the general reader, and the other is that the 1942 edition contains many passages that are now out-of-date. If the book is to retain its importance, which it has maintained since its first publication in 1917, a mild freshening in the form of commentary does not seem out of place.

Of its importance there is no doubt, but I must agree with Medawar when he says that its considerable influence ‘has been intangible and indirect’. I will shortly mention some of the facets which make the book so distinctive and unique, and all of these have contributed to its success. But I believe that the cardinal point is that D'Arcy Thompson was consistently able to examine subjects of significance in biology from a fresh point of view, and the mere fact that there was another point of view (sometimes one first imagined in early antiquity) comes as a shock, and therefore a stimulus, to those who so easily fall into the scientific fads and fashions of our day, and make little effort to look beyond the horizon of the ‘current views’.

The most conspicuous attitude in the book is the analysis of biological processes from their mathematical and physical aspects.