This book sterns from a course on Micromechanics that I started about
fifteen years ago at Northwestern University. At that time, micro-
mechanics was a rather unfamiliar subject. Although I repeated the
course every year, I was ne ver convinced that my notes have quite
developed into a final manuscript because new topics emerged con-
stantly requiring revisions, and additions. I finally came to realize
that if this is continued, then I will never complete the book to my
total satisfaction. Meanwhile, T. Mori and I had coauthored a book in
Micromechanics, published by Baifu-kan, Tokyo, in Japanese, entitled
1975. It received an extremely favorable response from students and
researchers in Japan. This encouraged me to go ahead and publish my
course notes in their latest version, as this book, which contains
further development of the subject and is more comprehensive than the
one published in Japanese. Micromechanics encompasses mechanics related
to microstructures of materials. The method employed is a continuum
theory of elasticity yet its applications cover a broad area relating to
the mechanical behavior of materials: plasticity, fracture and fatigue,
constitutive equa- tions, composite materials, polycrystals, etc. These
subjects are treated in this book by means of a powerful and unified
method which is called the 'eigenstrain method. ' In particular,
problems relating to inclusions and dislocations are most effectively
analyzed by this method, and therefore, special emphasis is placed on
these topics.