Nae ae An extensive survey of the atoll was last carried out in 1964, when the emphasis was on examining the radioactivity of flora and fauna and obtaining large numbers of samples of rats, birds, soils, and marine life for laboratory anaiysis. Thus, the gathering of additional samples of these types on this survey was not a primary requirement. However, a fairly large number of soil samples were taken and brought back for analysis so that the in situ measurements could be supplemented by calculations based on the isotopic concentrations determined by laboratory gamma ray spectroscopy, radiochemistry, and lithium drifted germanium spectroscopy. The external radiation survey techniques utilized were largely those developed and used by the Health and Safety Laboratory for the past several years in conducting detailed investigations of the properties of the external radiation environment in the United States*'*°*. fap em ne In addition to the survey measurements an experiment of the radiological effects of clearing a particularly heavily vegetated area was carried out on Bikini Island near the beginning of the survey trip. Besides the authors, who were primarily responsible for the external radiation measurements, the survey team included Edward Held, University of Washington Marine Radiobiolcgist, the survey leader; his assistant, Robert Erickson; Arnold Joseph of the Division of Biology and Medicine; Led + aes James Hiyane, Trust Territory District Agriculturist; Jack Tobin, former Trust Territory District Anthropologist; and Francis Tomnovek and Edward Jones of the U. S. Naval Radiological Defense Laboratory (USNRDL) who conducted most of the TLD studies and supplied and serviced the G-M detectors. The survey team spent a total of 16 working days on the atoll using a U. S. Trust Territory ship, the M. S. Militobi, as a base of operations. Fourteen islands and the two island complexes were surveyed. Only the very small island of Adrikan in the southwest corner of the atoll was bypassed. About ten days were spent on the three large sete nd islands, particularly Bikini Island (seven days). All of