Picking up shells is certainly one beach experience. All those colors, shapes and textures! Those who don't know an oyster from a conch shell, though, may wish to bring along a guide. Usborne Books publishes two good ones written by Graham Saunders, illustrated with color photos by Mike Freeman, and suitable for ages 8 and up. Shells is pocket-sized and includes a fascinating section on the biology and life cycle of a mollusc. Shells Sticker Book boasts eight pages of stickers to be affixed to the appropriate place in the text.