As editor I want especially to thank Dr. Ernst Freese for helpful co-
operation in preparing these volumes, and to express my appreclatlOn to
Drs. Kurt Hirschhorn and Marvin Legator, the other members of the
editorial board. Alexander Hollaender January 1971 Preface The purpose
of these volumes is to encourage the development and ap- plication of
testing and monitoring procedures to avert significant human exposure to
mutagenic agents. The need for protection against exposure to possibly
mutagenic chemicals is only now coming to be generally realized. The
recently issued Report of the Secretary's Commission on Pesticides and
Their Possible Effects on Health (the Mrak Report-U.S. Department of
Health, Education and Welfare, December 1969) has made an important
start. Its Panel on Mutagenicity recommends that all currently used
pesticides be tested for mutagenicity in several recently developed and
relatively simple systems. Whether recommendations such as these are
actually put into effect will depend on convincing government, industry,
and the public that the problem is important, that the proposed tests
would be effective, and that they can be conducted at a cost that is not
prohibitive. Why is it important to screen environmental agents for
mutagenic activity? To those who will read this book, the answer is
self-evident. The sine qua non of all that we value and all that we are
is our genetic heritage.