The early 1950s saw major concern
developing in all countries about the effects
of ionizing radiation. Not only was the horror
of the Hiroshima and Nagasaki bombings
fresh in everybody's memory, but three
countries, by testing new nuclear devices in
the atmosphere, had started to spread
radioactive material world-wide. The effects
of such radioative fall-out were largely
unknown and speculation was rife about the
health consequences of that widespread
exposure to radiation.
From the Foreword.