Radiobiological studies that are environmental in scope became, with the release of atomic energy, a mandate on the twentieth century. Environmental studies are not new. They have been implicit in thousands of biological research efforts, large and small, for generations. Atomic energy, however, is a new factor. Also new is the intensity of the approach. Not until the explosion of inquiry of this century has man brought together the necessary resources—the time, the funds, the instruments, the ingenious technological devices, the ideas, and the organizational and management skills—to attack problems that are global in scale. The atom as a tool of the environmental radiobiologist has, of itself, solved few problems. Its significance is that it has speeded up—to a degree still not fully tested—our ability to study ecosystems and their relations to each other. The First Twenty Years _Instruments for environmental research._ [Illustration: _A radiation analyzer for laboratory examination of field samples._] [Illustration: _Installing environmental research equipment in the field._] The first two decades of the Atomic Age have comprised a period of swift maturity. Much has been done to gain perspective. Atomic energy as a potential force for destruction has not been controlled. But there is a surer knowledge of the hazard inherent in the absence of control and a rational hope that the new power will be directed toward peaceful objectives. We know that: 1. The uninhibited release of nuclear products into the environment of the earth will create problems—fundamentally biological problems—of long duration and of still-unassessed ultimate effect. 2. Use of atomic weapons in war could have a “biological cost” beyond calculation. Yet, in terms of constructive employment of atomic resources, we also know that: 1. Atomic energy may help solve the very problems that the new age presents. 2. Careful and controlled development of atomic forces will provide the reservoirs of energy that will be needed to sustain the world’s populations of the next century and beyond. In whatever case, the solutions lie in the direction of environmental knowledge. Man, the human animal, will live in the environment he has the intelligence to understand and to preserve. [Illustration: “_... All creatures are linked to each other ... in their dependence on limited environments that together form the whole of nature ..._” (_Page 3_). (_White-capped noddy tern nesting colony, Engebi Island, Eniwetok Atoll, photographed in 1965._)] SUGGESTED REFERENCES Basic _Sourcebook on Atomic Energy_, Samuel Glasstone, D. Van Nostrand Company, Inc., Princeton, New Jersey, 1958, 641 pp., $4.40. What is Ionizing Radiation?, Robert L. Platzman, _Scientific American_, 201: 74 (September 1959). Weapons Testing and Fallout