Gilbert Cook was born at Blackburn (Lancashire) on 26 October 1885. He was the third of the four sons of William Cook and his wife Betsy Alice Livesey) both of Blackburn, and later of Garston, near Liverpool. So far as is known, none of his forebears had any marked interest in science. The first school he attended was the Public Higher Grade School, Blackburn, at which he remained till he was ten years old. From then till 1902 he was a pupil of the Roomfield School, Todmorden (Yorkshire). Up to the age of fourteen he showed no marked aptitude for mathematics, being more than once (so he himself related) at the bottom of the class and he actually failed in the Oxford Senior Local Examination. He then came under the direct influence of Joshua Hoyle, M.A., the headmaster, and Esca Sutcliffe, B.A., the science master, and it was mainly due to the latter that he owed the change in outlook which was quickly manifested in a change in performance. At the age of sixteen he won a West Riding of Yorkshire County Scholarship as well as the James Gaskell Entrance Scholarship to Owens College, Manchester, and also a University Entrance Scholarship awarded on the results of the preliminary examination held in schools. He always looked back to the years he spent at Roomfield with gratitude to his teachers. It was a school well equipped for science teaching and much in advance of the standard then prevailing. Its courses in both theoretical and practical chemistry more than covered the requirements of a first year university course. It had, moreover, what was rarer at that time, an excellent physics laboratory. Until he left school Cook had no definite views about the calling he would like to follow. His scholarship successes opened the way to a university instead of the business careers followed by his relatives. It was at the suggestion of his headmaster that he decided upon civil engineering even though he had no family connexions in that profession.