Many corporations, in their attempt to create innovative products and services, have focused on the concept of building teams. While many groups fizzle, on rare occasions the members of a group will experience an extraordinary eruption of excitement, transcending an organization's rigidconfines to achieve astonishing results. These individuals, say Jean Lipman-Blumen and Harold J. Leavitt, are lucky enough to be members of a "hot group," a phenomenon they lucidly and enthusiastically describe in their ground-breaking new book Hot Groups. A hot group is not a name for a newfangled team, task force, or committee. Rather, a hot group is defined by a distinctive state of mind coupled with a style of behavior that is intense and sharply focused on its ultimate goal. Stretching themselves beyond their own expectations, members of ahot group plunge into enterprises that have the potential to change, even ennoble, their own and others' lives. Neither trendy fabrication nor new management fad, hot groups have existed since the dawn of civilization, perhaps invigorating groups of cavemen to hunt together furiously for food before winter's approach. Today, examples of hot groups abound in territories such as Silicon Valley, whereimpassioned people have blazed paths through the burgeoning computer industry. Consider the hot group that created the original Macintosh and revolutionized the personal computer market. John Sculley, who joined Apple in the early 1980s, described a "magnetic field" that surrounded the Macintoshhot group members, and Bill Gates, Microsoft's mastermind, reported that a hot programming group to which he once belonged "didn't obey a 24-hour clock." Instead, they programmed for days at a time, pausing only to eat and talk about software with fellow programmers. Here also are examples of hotgroups at work in other industries: the individuals that created the blockbuster TV drama "Hill Street Blues"; the Navy and civilian personnel that transformed a standard cruiser into a guided missile cruiser in less than 12 months; and even the ad hoc crisis management group advising PresidentJohn F. Kennedy during the Cuban Missile crisis. Indeed, the inspiring case studies found throughout Hot Groups illustrate that well-nourished hot groups can profoundly transform any type of organization. Still, Lipman-Blumen and Leavitt recognize the risks inherent in loosening an organization's structural soil enough to accommodate these groups. Consequently, they address such issues as how to provide the kind of leadership required by a hot group, how to mesh a hot group with the regimentedstructure of the overall corporation, how managers can encourage new hot groups, and how best to cope with an overheated hot group. Drawing on decades of research and experience with groups and organizations throughout the world, Lipman-Blumen and Leavitt have written an intensely engaging book about a phenomenon that will become increasingly important in our rapidly changing world. Expertly carving a path through thisunmapped terrain, they lucidly demonstrate how managers and executives can ignite hot group sparks in their own organizations.