This is a great classic and a masterpiece of out-of-the-box thinking. I like it because it puts mathematic and physics back into biology, which has been completely dominated by genetics for the last 50 years. The point of the book is that there are some mathematical/physical constraints on body forms in nature, that just have to be the way they are, without needing any input from genetic instructions. Since this book was published in 1917, it has lost nothing of its potency and beauty, but the message in it has been neglected for too long. As a result, the creationists have been able to exploit this and keep asking where is all the information to make a body? And how did it get into the genome? This book provides part of the answer, long before DNA was discovered: Some aspects of bodily form do not need to be encoded in DNA, they are already encoded in the laws of nature itself. DNA works in the context of an external physical world and mathematical constraints, which add additional information. Therefore the genome does not have to include all the information to make a living being. The same of course applies (not discussed in d'Arcy's book) to molecules themselves: How protein fold is not encoded in DNA. This is determined by physics. I think physicists and biologists need to work closer together. This book provides the clarion call, although it is almost 100 years old. ( )