INTRODUCTION 
YEAR by year nature study becomes more and more 
popular, and countless books continue to appear describ- 
ing the life histories of animals, birds and insects, but 
descriptions of fish life do not seem to have had their 
fair share of attention. 
This is not because fish are less interestmg than 
birds or mammals, but chiefly because of the difficulty 
of observing them in their native element. 
I have endeavoured in this book to show how fish 
reveal to the observer their intentions and emotions 
by attitudes, movements and changes in colour. I 
have described the eggs and the early life histories 
of a few of our commoner fishes, and how the adult 
fish is assisted in the battle for existence by concealing 
coloration and other devices. The habits of a few 
marine animals have been dealt with, and finally I have 
explained in detail how the various photographs shown 
have been obtained, in the hope that the information 
may be of assistance to those interested in fish photo- 
graphy. 
If observations and_ illustrations of concealing 
methods are to be of any real interest, it is necessary 
that fish should be watched and photographed while 
