You'll find a number of varieties at the farmer's market right now, but for a cook's purposes, they divide into two categories: watermelons and everything else. Watermelons have an airy network of cells that gives them a light, mealy consistency, while the "cantaloupe kin" have a dense, aromatic flesh that oozes sweet juice down your chin. The two are only distant cousins: cantaloupe-type melons are more closely related to cucumbers than they are to watermelons.
Photos by Melissa Schneider