The Codex Gigas contains five long texts as well as a complete Bible. The manuscript begins with the Old Testament, and it is followed by two historical works by Flavius Josephus who lived in the first century AD. These are The Antiquities and The Jewish War.
After Josephus is the most popular Encyclopaedia of the middle ages, by Isidore, who lived in the sixth century in Spain. This is followed by a collection of medical works, and these are followed by the New Testament.
The last of the long works is a Chronicle of Bohemia by Cosmas from Prague (ca 1045-1125). This is the first history of Bohemia and important work.
There are also some short texts in the manuscript. The first, before the picture of the Heavenly City, is a work on penitence. The second, after the Devil portrait, is on exorcising evil spirits. The last important short work is a Calendar, containing a list of saints and local Bohemian persons on the days on which they were commemorated. There is also one lost work, on leaves that have been cut out of the manuscript, the Rule of St Benedict, the essential guide to monastic life written in the sixth century.
The most important book of Christianity is the Bible. The other texts in the Codex Gigas were carefully chosen to accompany it because together they provided information about Jewish history (Josephus), universal knowledge (Isidore), medicine, and local history (Cosmas).