This book gives a great psychological look into the challenges of leaving a stagnant job to find rewarding work. It definitely motivated me (as well as gave me direction) to begin making the changes needed to improve my life. Transitions went well beyond the cliches and empty pointers that so many books like this fall into.
William Bridges wrote this book when he first started work in the area of transitions. He lays out well the 3 stages of transition - ending, neutral zone, beginning. He intersperses stories of how he developed his theory, too. This is a good starting point if you are an individual. However, I think Bridges' best book is Managing Transitions: Making the Most of Change.