《变分法(第3版)》是一部经典图书，书中分为3部分，第一部分主要阐述变分法中的经典直接法及其扩张，第二部分讨论极小极大化方法，第三部分介绍变法中的新理论。适用于数学及相关专业的研究生和研究人员。

First 6 chapters include theory of fields and sufficient conditions for weak and strong extrema. Chapter 7 considers application of variation methods to systems with infinite degrees of freedom, and Chapter 8 deals with direct methods in the calculus of variations. Problems follow each chapter and the 2 appendices.