Precision measurement with gravity

Summary form only given. The author describes some of the work directed towards the measurement of G, g, and g/spl mu//spl nu/. A number of recently completed measurements of G have had, and a number of ongoing measurements have, the aim of improving the accuracy of the first of these "gs" from today's 1.5 parts in 10/sup 2/ to better than one part in 10/sup 4/ (to somewhat better than the accuracy with which it was thought to be known 10 years ago). By contrast, our ability to accurately measure the second "g" has, during the past forty years, enjoyed a remarkable 3 orders-of-magnitude improvement. Lastly, sometime in the next decade or so, the final "g" can be expected to provide us with new insights into things such as the formation of massive black holes and galaxy evolution as well as a variety of other objects of astrophysical interest. The role of precision measurement science in carrying out these measurements, and, indeed, in underpinning all of scientific progress, is highlighted. Finally, the commonality of these three different measurements is pointed out.