As I'd never done more than take a tentative nibble, I telephoned Kasma Loha-unchit, a bitter-melon devotee and Thai cooking teacher who runs a school in Oakland, California, called The Art of Thai Cooking. Would she consider making me a bitter-melon lunch? I asked. She graciously agreed, and so, on a sunny afternoon, we sat down to a mouth-puckering feast: sliced raw melon with a pungent shrimp-paste dipping sauce; lightly stir-fried melon with egg; stewed melon with mustard greens and pork bones; and stir-fried melon with shrimp and fermented black beans. Loha-unchit's American husband, Michael Babcock, also a bitter-melon fan, joined us. ''It just makes me feel healthy when I eat it,'' he told me, smiling.