Word Index Builder creates word map (index) for text. Being built only once, such index allows to perform very quick search for given pattern by exact or approximate matching. Approximate (fuzzy) search implies, that target string differs from pattern in given number of positions. This number is configurable. Such way of search allows to find misspelled words, or words having unknown spelling. This tool becomes especially effective when search is being performed multiple times for numerous patterns in the same text. One-time preprocessing takes time proportional to text length. After that, all consequent searches are pretty fast. Word index can be saved to file and then loaded. Search results are being shown in a convenient form of tree, where upper level displays found case, and underlying level shows all contexts of this case. So you see the result as a concordance (special form of dictionary , containing citations of the passages in which the words occur). Ellipsis button next to each node of the tree allows to jump to the found position in original text, displayed in the right pane. Source data for Word Index Builder is plain text, which can be loaded either from file or from clipboard. The program does not affect source document in any way. Saved index file includes a local copy of the source text.