Book excerpt: The most essential thing in the world to any individual is to understand himself. The next is to understand the other fellow. For life is largely a problem of running your own car as it was built to be run, plus getting along with the other drivers on the highway. From this book you are going to learn which type of car you are and the main reasons why you have not been getting the maximum of service out of yourself. Also you are going to learn the makes of other human cars, and how to get the maximum of co-operation out of them. This co-operation is vital to happiness and success. We come in contact with our fellowman in all the activities of our lives and what we get out of life depends, to an astounding degree, on our relations with him.