A COMPENDIOUS guide to "the vegetables, fruits, grains, nuts, spices, and culinary herbs of our planet," Jon Gregorson`s The Good Earth (Whitecap, 211 pages, $14.95 paper) demonstrates that our favourite foods can be interesting as well as tasty and nutritious. The book is somewhat dry in tone - information is obviously more the aim than entertainment - so it can get boring if much is read at a stretch. But it`s the perfect volume to dip into while waiting for the kettle to boil or killing time before dinner. Each entry combines a description, historical background, summary of uses, serving suggestions, and miscellaneous tidbits, some of which are quite surprising. To give you a taste: a peach or two will occasionally grow on almond or nectarine trees; "capers thrive particularly in ancient ruins"; vanilla is the product of a type of orchid; and, notwithstanding the p.r. campaign for eating an apple a day, that glossy Delicious or juicy Mac is actually far less nutritious than other fruits. I would have welcomed less detail about common foods (who needs to be told, after all, that carrots range "in shape from long and thin to short and wide"?) and more on such exotics as amaranth grain and the tomatillo. Nevertheless, The Good Earth is a handy guide, guaranteed to appeal to those who want to have their kale and read about it, too.