This book is the result of a similar process. Some 15 years ago， I joined the faculty in thesolid mechanics group in the Division of Engineering at Brown University. I am a proudgraduate of an institution that considers inhaling the air once breathed by Isaac Newtonto be more educational than taking graduate courses. Consequently， I started at Brownwith lungs and head filled with erudite air but knowing far less about solid mechanics thanthe students in my classes. I have spent the intervening years attempting to remedy thissituation， principally by eavesdropping on the conversations of my colleagues， who are allgenuine and highly respected experts in solid mechanics. This book summarizes what Ihave learned.