It has been just thirty years since this volume, Modern Theory of Polymer Solutions, was published by Harper & Row, Publishers. It is now out of print but is still in some demand. Furthermore, it is also an introduction to the author’s new book, Helical Wormlike Chains in Polymer Solutions, published by Springer-Verlag in 1997, although
some parts of it are now too old and classical and have only the significance of historical survey. Under these circumstances, the author approved of the preparation of this electronic edition without revision at the Laboratory of Polymer Molecular Science, Department of Polymer Chemistry, Kyoto University. On that occasion, however, he attempted his efforts to correct errors as much as possible. Finally, it is a pleasure to thank Prof. T. Yoshizaki, Mrs. E. Hayashi, and his other collaborators for preparing this electronic edition.