Graduate Theology

2nd edition. Washington, DC: Gale, 2003. 15 volumes + 4 supplements (2009, 2010, 2011, 2012-2013).
For print version locations, see the UofT Library Catalogue.
This work is the major English-language encyclopedia on Catholic topics. It contains some 17,000 articles, each with a bibliography. The 2003/online edition includes multiple supplements with articles on topics of current interest. Unfortunately many of the articles in the 2003/online edition are reprints from the 1967 edition without any updating or merely with a few changes in the bibliography. The 1967 print edition of the New Catholic Encyclopedia includes some articles on topics not included in the 2003/online edition of the New Catholic Encyclopedia.

Grand Rapids, MI: Eerdmans, 1999 — 2008. 5 volumes.
For print version locations, see the UofT Library Catalogue.
This work is the major English-language theological encyclopedia from a Protestant perspective. It emphasizes post-Reformation and particularly contemporary Christianity. The articles are substantial, but selective; there are many topics which are not addressed. Many of the articles are translated from the German-language Evangelisches Kirchenlexikon (1986-1996).

Still in its infancy (it only has forty articles so far), this open access resource, sponsored by St Mary’s College of the University of St Andrews and the John Templeton Foundation, promises to be a major reference work in the future.

New York: Encyclopedia Press, 1905–1922. 16 volumes + 2 supplements.
For print version locations see the UofT Library Catalogue.
For over fifty years this work was the chief source of information on the Catholic Church in English-speaking countries. Owing to its length (it has almost twice as many words as the New Catholic Encyclopedia) and its emphasis on historical articles, it is still useful for some topics. In some articles the writers adopt an apologetic, even polemical, approach.

Edited by Karl Rahner et al.
New York: Herder & Herder, 1968. 6 volumes.
The articles in this encyclopedia are each several pages in length and make significant use of the documents of Vatican II. They are written by some of the most important Catholic theologians of the 1960s.
Four volumes are available on the Internet Archive, a trusted source, but one for which it is necessary to create a free account and login: Volume 1, ABS-CON, Volume 2, CON-GRA, Volume 5, PHI-SAL, Volume 6, SCA-ZIO.
An abridged version of this work published in 1975, Encyclopedia of Theology: The Concise Sacramentum mundi (online), includes some totally revised articles.

Edited by A. Vacant and E. Magenot.
Paris: Letouzey et Ané, 1908–1949. 15 volumes.
For print version locations, see the UofT Library Catalogue.
Universally regarded as one of the most authoritative works in its field, this encylopedia covers all aspects of theology. It includes many very long articles with extensive bibliographies.
All volumes are available on the Internet Archive, a trusted source, but one for which it is necessary to create a free account and login: tome 1:1, A-APO; tome 1:2, APO-AZZ; tome 2, BAA-CIS; tome 3, CLA-CZE; tome 4, DAB-EMS; tome 5:1, ENC-EUC; tome 5:2, EUC-FIU; tome 6:1, FLA-GEO; tome 6:2, GEO-HIZ; tome 7:1, HOB-IMM; tome 7:2, IMP-IRV; tome 8:1, ISA-JEU; tome 8:2, JOA-LAT; tome 9:1 LAU-LYR; tome 9:2, MAA-MAR; tome 10:1 MAR-MES; tome 10:2, MES-MYS; tome 11, NAA-PAU; tome 12:1, PAU-PHI; tome 12:2, PHI-PRE; tome 13, PRE-ROS; tome 14, ROS-SZC; tome 15, TAB-ZWI.