While it is said, with some truth, that man's greatest conflict is with man, and although that conflict shows little indication of soon abating, he faces other conflicts which are also very real and immediate. Man is one of the many competing species in the world's interdependent fauna and his very existence is inextricably interwoven with that of the other animals in his environment. Man's progress may be measured largely by the degree to which he has been able to shape his environment to meet his needs and few would deny that in so altering his environment he has made human existence more tolerable and consequently, more satisfying. At least few of us would elect to return to a more primitive stage of human history.