Cambridge's new McDonald Institute for Archaeological Research owes its origin to the generosity of Daniel McLean McDonald, and it is an appropriate act of pietas that the Institute's first monograph should be a collection of his writings. Dr McDonald was fascinated by systems of weighing and measuring and his investigations ranged from Egypt and Sumer through Classical times to the Middle Ages and the New World. He saw very clearly how the use of liquid to measure capacity imposed a relationship between units of weight and those used to measure volume and hence length; and for him the units employed by the ancients possessed a coherence that reflected a very pragmatic understanding of the real world. His writings on metrology do not seem to have been intended for publication and they may appear somewhat cryptic to the uninitiated, and some of his hypotheses on the relationship between various systems are, to say the least, bold - but it is from such speculations that understanding grows, and understanding intelligence and its origins is one of the aims of the McDonald Institute and its new Cambridge Archaeological Journal.