If you think Great Britain's National Trust preserves only formal Georgian piles filled with horsehair sofas and portraits of anemic-looking ancestors, think again. The Trust currently maintains more than 200 stately houses, 150 gardens, and 500,000 acres of countryside and coast throughout England, Wales, and Northern Ireland. The National Trust Guide by Lydia Greeves and Michael Trinick (Abrams, $39.95) is the official index to the properties and an indispensable resource for visitors and serious Anglophiles. The often humorous text covers everything from St. Cuthbert's Cave in Northumberland to the delightfully named Burrow Mump, a Somerset hill topped by an 18th-century church ruin. Also included: dovecotes, theaters, London streets, windmills, even a printing press. Lush photography evokes the richness of this historical trove.