Beyond Pedigrees by Beverly DeLong Whitaker Genealogical Dictionary by Maurine & Glen Harris The SOURCE, A Guidebook of American Genealogy edited by Loretto Dennis Szucs & Dandra Hargreaves Luebking A Preservation Guide by Barbara Sagraves Map Guide to the U.S. Federal Censuses 1790-1920 by William Thorndale & William Dollarhide,this helps me understand what counties were where at the time.