Abstract
This work provides a thorough index of terms found in Ludwig Wittgenstein's On Certainty. The index includes not only every philosophical term found in Wittgenstein's text, but also many non-philosophical terms when they are used in highly charged philosophical contexts. In all, there are some 575 main entries. Moreover, a concerted effort is made to indicate in what connections a given term is used by adding subordinate qualifying phrases to the main entries. For crucial terms (e.g., 'know,' 'proposition,' 'doubt,' etc.) the sub-entries indicating context are quite extensive.