A climbing guide for the central Maryland. Basically any (and every) thing near DC and Baltimore, the 270 corridor is also covered very well. This book does not cover any climbing areas in western MD
CLimb Maryland! is a homegrown- and ridiculously thorough- collection of every scrap of route information of central Maryland climbing. Over 500 routes in 22 areas from Carderock and Rocks State Park, to hidden baltimore crags, Sugarloaf and Harpers Ferry and other spots you'll probably never go unless you live there.
Descriptions of areas and routes are excellent. Clear pictures and topos. Although, beware some routes look like 50ft top ropes in the photo and are actually 15 boulder problems ;)
Issues of Access, History and Geology are also given due attention, so for the real geeks out there, this book will keep you pumped full of tidbits to annoy your partner.
Gems: the Harpers Ferry section is a very thorough collection of historic, adventurous climbs. The Baltimore areas are also covered very well. Both these areas are barely given a glance in the Horst guide book to MD VA and WV.