This book stems from a course on Micromechanics that I started about
fifteen years ago at Northwestern University. At that time,
micromechanics was a rather unfamiliar subject. Although I repeated the
course every year, I was never convinced that my notes have quite
developed into a final manuscript because new topics emerged constantly
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
Japanese, entitled Micromechanics, published by Baifu-kan, Tokyo, in
1975. It received an extremely favorable response from students and re-
searchers 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 materi- als: plasticity, fracture and fatigue,
constitutive equations, composite materi- als, 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.