Physical activity and the capacity for work are such fundamental determinants of human survival that it may come as a surprise that their exact measurement on a population scale has only been achieved quite recently. The relevance of such assessments for ecological analysis in general, and of productivity in particular – the two major aims of the IBP – is pointed out by Professor Shephard in his preface to the present volume. Within the HA Section of the International Biological Programme the acquisition of data on physiological work capacity was from the start seen as an objective of the highest scientific and practical desirability. Difficult as it is to carry out physiological studies on large population samples (and even more difficult in the field) many international HA teams achieved this aim with an impressive degree of success, as this book makes clear. To Professor Lange Anderson of Norway, who acted as theme coordinator, goes great credit for his role in securing the interest of physiologists in many countries in this aspect of the HA programme.

A strong and long lasting impetus to this endeavour was given during the planning stages of the HA Section when decisions had to be made on test procedures which would find wide acceptance both for laboratory and field studies. The comparison and the validation of different techniques were successfully accomplished by a team from some 7 countries who worked in Toronto in 1967 (see Human Biology. A Guide to Field Methods.