Sir John Hammond was a man of two worlds, in both he won esteem and affection. In the academic environment of Cambridge he was the centre of a devoted and distinguished group of students and research workers, on the farm and in the market place he was welcomed not only as a scientific guide, but equally as a friend of all those engaged in the breeding and management of livestock. The postgraduate school in animal reproduction and growth of which Hammond was the centre and inspiration attracted workers from every part of the world. They came to him raw, some with a purely academic training and little or no knowledge of the practical applications of his work, others from a farming background with the minimum of academic qualification. It was Hammond’s particular genius in recognizing the qualities inherent in each, that enabled him to direct into productive lines of study and research everyone who sought to work under him. At times he was criticized by his more conservative colleagues for accepting postgraduate students, particularly those from overseas, with too low an academic standard, but rarely did he misjudge the potential value of his pupil. Some it was true might never make outstanding research workers, but these men had the qualities essential to the difficult task of carrying the results of research into practice, whether it was on an English farm, a South American ranch or an Australian station. As a result the men who worked with Hammond are to be found in vitally important posts throughout the world, not only as university teachers and research workers, but equally in the advisory and administrative services. There is hardly any corner of the world where the Cambridge school is not represented at the highest levels.