Encyclopedias

Encyclopedia of Early Christianity (2 vols.)
BR 162.2 E53 1997 Reference
Augustine through the Ages: An Encyclopedia
B 655 Z69 A84 1999 Reference
Encyclopedia of the Early Church (2 vols.)
BR 66.5 D5813 1992 Reference
The New Catholic Encyclopedia 2nd ed. (15 vols.)
BX 841 N44 2003 Reference

Dictionaries & Handbooks

The Oxford Dictionary of the Christian Church
BR 95 O8 2005 Reference
Westminster Dictionary of Church History
BR 95 W496 Reference
The Westminster Handbook to Patristic Theology
BR 162.3 M38 2004 Reference
Dictionary of Early Christian Literature
BR 66.5 L4813 2000 Reference
A Dictionary of Early Christian Beliefs
BR 66.5 D53 1998 Reference

Atlases

Historical Atlas of Christianity
G 1046 E4 L5 2001 Reference
Atlas of the Christian Church
BR 98 A74 1987 Reference
Atlas of the Roman World
DG 210 C6 1982 Reference

Other Useful Resources

The Early Christian World (2 vols.)
Patrology (v.1, 2, 3)
Patrology (v.4)
Matrology: A Bibliography of Writings by Christian Women from the First to the Fifteenth Centuries
Z 7751 K33 1995 Reference