This book explores the ways in which people's work careers are changing as the organizations in which they work are changing. The old concept of the firm as a a self-contained entity interacting mainly with its customers has been replaced by the reality of firms whose boundaries have given way to new alliances with suppliers, sometimes competitors, and other outside organizations, in ways that require a redefinition of what a firm can expect from lifetime employment. At the same time, the workers in these careers are interrupted by layoffs, or changed by new technologies, and over their work life will be expected to maintain a habit of continuous learning to remain in the work force.