Heredity does make an important contribution, but far less than usually assumed. At the same time, it would serve no purpose to set up the false opposition of environment to genetic inheritance. No such split exists in nature, or in the mind of any serious scientist. If in this book I emphasize environment, I do so to focus attention on an area that most books on the subject neglect and none explore in nearly enough detail. Such neglect frequently leads to crippling deficiencies in what people are offered by way of treatment.
