THE GENEALOGIST'S ADDRESS BOOK (4TH EDITION)
by Elizabeth Petty Bentley. Baltimore: Genealogical Publishing Co., Inc., 1998. I haven't gotten completely through the book yet, but I've liked what I've been able to use so far. There's more than 25,000 listings of resources, divided and catagorized within four groups (National Addresses, State Addresses/American Trust Territories, Ethnic & Religious Organizations and Research Centers, and Special Resources). It was a great birthday present!