A wide-ranging if narrowly focused inquiry that's of interest mainly for its chatty briefings on how top corporate executives have arranged (or failed to provide) for orderly successions. Originally, Sonnenfeld (Harvard Business School) assumed that aging CEOs were no different from other older workers. After five years of research on 300-odd retirees, however, he concluded that captains of industry comprise a distinctive group. Among other significant divergences, they tend to cast themselves in heroic molds and to judge their contributions by standards unlikely to be applied by subordinates. In consequence, the author's largely anecdotal evidence amounts to a conceptual examination of the corporate leader's role in late career, not a guide to planning harmonious and effectual management transitions. Sonnenfeld identifies four principal types of departure style. For openers, there are monarchs who, unwilling to leave office voluntarily, either die in harness or are ousted. Along similar lines, generals exit reluctantly and spend much of their free time ""plotting a return to active service."" By contrast, ambassadors withdraw gracefully, retaining loose ties to their organizations, and governors quit promptly to pursue new interests. A wealth of well-known names adorn the roster of CEOs whose leave-takings Sonnenfeld logs either from interviews or audits of proxy statements and other public records. Their ranks include the once-powerful likes of John deButts (AT&T; Harry Gray (United Technologies); Winthrop Knowlton (Harper & Row); Edwin Land (Polaroid); William Paley (CBS); Irving Shapiro (Du Pont); and Thomas J. Watson (IBM). Covered as well are family firms whose entrepreneurial and heritor chieftains are apt to hold on for dear life. An offbeat but generally absorbing collection of case studies that offer about equal measures of personal and pedantic insights.