There are many books on theology in the Grace Library collection!
To find them, try searching the Discovery service (below) by clicking Books then adding a proper name or a descriptive keyword. For example, search a particular religious leader's name such as 'Dalai Lama', or for 'God', 'theology' or 'theologie' to see what is available in the library collection.
Listed below are encyclopedias that have overview articles that describe persons, ritual practices, religious faith, and other theological concepts. You will find in the reference collection that there are other types of books that are more specific as well! Some examples are:
Atlas - as a collection of maps, you expect an atlas to define geographical features, but some editions include geopolitical, social and religious information
Concordance – use these to find every verse from a primary text, such as the Bible, in which a word appears
Commentary – gives verse by verse help in interpreting the primary source texts
Dictionary – briefly defines biblical words and concepts