This book is aimed principally at university, college and polytechnic students who wish to understand concrete for the purpose of using it in professional practice. Because the book is written in English and because it uses both SI and the so-called old Imperial units of measurement, the book is of interest and value in many countries, probably world wide. The large incidence of material (as distinct from structural) failure of concrete structures in recent years bridges, buildings, pavements and runways is a clear indication that the professional engineer does not always know enough about concrete. Perhaps, in consequence of this ignorance, he or she does not take sufficient care to ensure the selection of correct ingredients for concrete making, to achieve a suitable mix, and to obtain a technically sound execution of concrete works. The effects of climate and temperature, and of exposure conditions, do not always seem to be taken into account in order to ensure lasting and durable concrete structures.