At once seductive and exasperating, this stylish work by British writer Tweedie expatiates on human love--its origins, modern conundrums, and more viable future alternatives--in a brisk but somewhat tendentious manner. Occasionally echoing staunch feminist Adrienne Rich and chic commentator Nancy Friday, drifting now and then into muted millennial tones, she draws frequently on proper sources (Plato to Erasmus to Dorothy Dinnerstein) and her own not entirely representative experience (two shaky marriages before a strong third) in pursuing her unsentimental journey: traditional love, based on mutual dependencies and the assumption of female inferiority, is now obsolete; in future, love must build from true equalities to reflect women's modern opportunities and newly acquired independence. Tweedie ranges freely and confidently, searching out love's evolutionary purposes, tracing the emergence of romantic love, offering some sudden verities--on the women of violent men, for example, or the connections between love and economic stability. But right alongside the astute observations are striking provocations (""before the industrial revolution, there was no Oedipus complex""), unfortunate excesses, and some nettling unfounded statements (most parents still prefer sons). What of future love? ""Both sexes share one overwhelming necessity--to begin to use what is still virgin territory, the reasoning function of the neo-cortex. . . . Reason is the new territory, the source of kindness, charity and unselfishness, the root and core of our future transformation into superhumans."" This, then, ends as a sermon of sorts, disarming in spots, circuitous in its development, and vulnerable in its conclusions. But some will take heart.