This dissertation is about wisdom and texts about wisdom. It studies four Old English lexemes for 'wise,' snotor, gleaw, frod, and wis, respectively, as a way to define wisdom and wisdom literature in Old English. On the levels of characterization, narrative, and theme, wisdom performs often essential functions in a variety of Old English texts, most intensely in poetry and frequently in texts outside the approved canon of Old English wisdom literature. Wisdom literature has long been a recognized genre, but its definition and canon remain disputed because of a lack of attention to fundamental questions of what wisdom is, where it resides, and what it does. Wisdom literature in Old English, I suggest, should be defined generically according to how its texts explicitly invoke wisdom. Moreover, not all wisdom is the same. Old English poetry, differently from prose, presents wisdom as a psychological ability defined by intellectual processes and expressed verbally in social situations. In poetry, words for wisdom collocate characteristically with mental vocabulary to establish wisdom as a conceptual entity located in the mind and to explain how this wisdom is activated by thoughtfulness and fulfilled through speech events. Data have been collected comprehensively from throughout the Old English corpus and emphasis is on primary texts. This dissertation challenges conventional wisdom by means of a lexical approach that clarifies the definition of wisdom in Old English, gives us a way to access an Anglo-Saxon understanding of literature about wisdom, and accordingly alters and revitalizes the canon of Old English wisdom literature. A revised canon of wisdom literature in Old English includes, for example, long narrative poems such as Elene and Daniel which have been ignored as wisdom poems because their formal structure does not fit preconceived ideas about the forms wisdom can take in Old English.