Cook was born in
Felsted, Essex in 1922. He was the eldest of the six children of Reginald Thomas Cook, a
customs and excise officer, and his wife, Ethel, Saxon. His family were active in the
Congregational church; Cook became a lifelong Christian. He was initially educated at the village school at Felsted, then at West Leigh School in
Leigh-on-Sea. From 1933 he attended at
Westcliff High School for Boys, a
grammar school in
Westcliff-on-Sea. In 1939 he won a scholarship to attend university at
Corpus Christi College, Cambridge, beginning in 1940. As an
undergraduate, he studied the
natural sciences tripos, selecting courses in
physical sciences,
biological sciences, the
history and philosophy of science and
geology. He received his
Bachelor of Arts degree in 1943. Cook graduated during
World War Two, so
was conscripted into military service. He was assigned to the Admiralty Signals Establishment (now part of the
Admiralty Research Establishment) as a temporary experimental officer, in the field of
electronic counter-measures. After the war he returned to Cambridge to study for a
doctor of philosophy (PhD) degree under the
supervision of
Edward Bullard and B. C. Browne. His
PhD thesis was on precise measurements of gravity in the British Isles. ==Academic and scientific career==