What makes someone a guru (the Sanskrit word originally meant ``one who brings light out of darkness'')? Why are some gurus particularly dangerous? This thoughtful and engaging book provides answers and a host of interesting insights. Storr, a British psychologist who teaches at Oxford and has written a number of well-received books (Solitude, 1988; Music and the Mind, 1992, etc.), profiles religious or cult gurus (including Ignatius of Loyola, Georgei Gurdjieff, Rudolf Steiner, Bhagwan Rajneesh, Jim Jones, and David Koresh) and two intellectual ones, Freud and Jung. As his title and his choice of subjects in the first category reveal, he views most gurus as being emotionally unbalanced and possessing many highly unappealing qualities: They tend to be loners, have experienced profound psychological crises (sometimes involving psychosis), and generally relate poorly to others. Most are arrogantly self-certain and otherwise highly narcissistic, even grandiose; some tend to be paranoid while others, such as Rajneesh and Koresh, are materially or sexually exploitative of others. In the last third of his analysis Storr approaches his subject thematically, comparing gurus both to those who are scientifically or artistically creative, and to the mentally ill, particularly schizophrenics. In his wide-ranging, unabashedly antiguru final chapter, he engages in a fascinating if frustratingly brief contrast of the ``charisma of power'' and the ``charisma of certainty'' with the more benevolent ``charisma of goodness.'' It is unfortunate that Storr does not write about more appealing gurus in the latter category (he mentions only a few figures in passing), and also that he does not choose Jewish or Islamic gurus (the Lubavitcher Rebbe and the Ayatollah Khomeini come to mind) or political gurus (Storr does allude briefly to Lenin, Churchill, and de Gaulle). However, what he has focused on still provides an extremely useful and for the most part well-crafted introduction to an intriguing and important subject.