Cinnamon Bay Plantation was the ideal Caribbean island getaway-or so it seemed. But for distinguished Harvard economist Henry Spearman it offered diversion of a decidedly different sort and one he'd hardly anticipated: murder. While the island police force is mired in an investigation that leads everywhere and nowhere, the diminutive, balding Spearman, who likes nothing better than to train his curiosity on human behavior, conducts an investigation of his own, one governed by rather different laws-those of economics. Theorizing and hypothesizing, Spearman sets himself on the killer's trail a.