This book presents methods for computing correlation equations. All the topics treated hefe are eluci­ dated in terms of concrete examples, which have been chosen, for the most part, from the Held of analysis of the mechanical properties of steel, wood, and other materials. A necessary prerequisite for any study of correlation equations is so me knowledge of the moments of random variables. In the Appendix, there is provided a brief treatment of moments, as well as a discussion of the simplest methods of computing them. We have paid particular attention in this book to the techniques of computing correlation equations, and to the use of tables for alleviating the computationalload. The mathematical bases of the methods used in setting up correlation equations are expounded in the books cited at the end of this volume. A. M. December 1965 PIe ase note that the abbreviation 19 is used in this book to designate the logarithm to base ten, Note further that the comma has been retained as the decimal point in tabular material.