BOOK REVIEW : Idea of ‘Flow’ Ebbs With Mixed Messages : THE EVOLVING SELF: A Psychology for the Third Millennium <i> by Mihaly Csikszentmihalyi</i> ; HarperCollins $25, 350 pages

Following a 15-year study that involved paging workers at five Chicago companies for interviews at various times of day, University of Chicago psychology professor Mihaly Csikszentmihalyi (pronounced Chick-SENT-me-hi ) came up with the most precise description we’re likely to have of a state as elusive as human happiness.

He called it “flow” and found to his surprise that it was strongest not when his interview subjects were taking English lavender baths or watching TV dramas but when they were absorbed in fulfilling tasks. By becoming involved in projects challenging enough to avoid boredom and yet feasible enough to prevent anxiety, Csikszentmihalyi’s subjects found their self-consciousness swept away, however briefly, by a sense of purpose and harmony.

When his findings were first popularized in his 1990 book “Flow: The Psychology of Optimal Experience” (HarperCollins), they were well-received by aficionados and practitioners of psychology, who knew how rare it was to see their discipline investigate normal or optimum states of mind.

In this sequel to “Flow,” Csikszentmihalyi reaches out for a broader audience. He attempts to corral the self-help crowd by interjecting questions throughout the text (e.g., “In what area of life do you feel the greatest discontent?”) and he emphasizes that flow is attainable not just by the artist compelled to brush paint on canvas at 3 a.m. but by the mother teaching her son a new cookie recipe and by the worker focusing intently on an assembly line.

What Csikszentmihalyi most hopes will broaden this book’s appeal is its focus not simply on individual fulfillment but on social harmony. “The Evolving Self” is the kind of idealistic treatise that some of us dreamed about writing in young adulthood: one where we show how a more loving, wise and beneficent society can be founded on our good will and instinctive wisdom.

Unfortunately, while Csikszentmihalyi’s book is probably far more elegant and erudite than the adolescent treatise most of us might have written, it suffers from a similar failing: Its high ambitions--to “summarize the principles that make life worth living”--exceed its author’s substantial abilities.

First, there’s the unclarity of the central metaphor itself: Csikszentmihalyi presents flow as a state where one is in harmony with one’s environment (as in “going with the flow”), but he also says it’s a state wherein one is able to distinguish oneself from that environment (as in “swimming against the current”). How one can do both at the same time is never really explained.

Second, his argument that a flow state can lead to a “greater complexity of consciousness” flies in the face of his acknowledgment that flow can only occur when a person comes to see the world as harmonious. For as he acknowledges, the world can only be seen as harmonious when one denies its true complexity (for that is beyond our ken) and uses myths and stories to simulate an understanding of it.

Csikszentmihalyi, in other words, may want us to view flow as a state that can lead to some magical social and individual enlightenment. But in fact, whether people find flow in rain dancing, meteorology or even in gang warfare (one of Csikszentmihalyi’s students found flow states in Japan’s notorious Kamikaze Bikers), it is just as likely to lead to prejudice as insight, ethnocentrism as objectivity, war as peace.