The collection of library materials falls under two main categories-religious and geographical. The primary religious area of collection is Mennonite denominations. The primary geographical area is Lancaster County and other counties in Pennsylvania where Mennonites have historically lived. The secondary area includes other religious denominations having aspects of commonality with Mennonites. Secondary geographical areas include other areas in Pennsylvania and other states and countries where Mennonites have migrated from the primary geographical area or have lived prior to living in the primary area. Materials include works on religious history, local history, social history (including genealogy), church life, and works in other subject areas useful as supporting material to the primary and secondary categories.