For over one hundred years, the Mathematical Association of America has been publishing high-quality articles on the history of mathematics, some written by distinguished historians and mathematicians such as J. L. Coolidge, B. L. van der Waerden, Hermann Weyl and G. H. Hardy. Many well-known historians of the present day also contribute to the MAA's journals, such as Ivor Grattan-Guinness, Judith Grabiner, Israel Kleiner and Karen Parshall.

Some years ago, we decided that it would be useful to reprint a selection of these papers and to set them in the context of modern historical research, so that current mathematicians can continue to enjoy them and so that newer articles can be easily compared with older ones. The result was our MAA volume Sherlock Holmes in Babylon, which took the story from earliest times up to the time of Euler in the eighteenth century. The current volume is a sequel to our earlier one, and continues with topics from the nineteenth and twentieth centuries. We hope that you will enjoy this second collection.

A careful reading of some of the older papers shows that althoughmodern research has introduced some new information or has fostered some new interpretations, in large measure they are neither dated or obsolete. Nevertheless, we have sometimes decided to include two or more papers on a single topic, written years apart, to show the progress in the history of mathematics.

We wish to thank Don Albers, Director of Publications at the MAA, and Gerald Alexanderson, former chair of the publications committee of the MAA, for their support for the history of mathematics at the MAA in general, and for this project in particular.