Summary: Wordcorr is a computational tool that assists linguists in comparing natural languages systematically. It splits the work involved in applying the Comparative Method. Your responsibility is to identify patterns in the data that may show common origin. The computer's responsibility is to keep track of your judgments in a framework from which you can draw evidence about the development of later languages from earlier ones. Wordcorr does not perform the analysis for you; it organizes the evidence that you consider relevant to the analysis. The tool was developed under a grant from the National Science Foundation. With an introduction featuring Sherlock Holmes and Dr. Watson. [This partial version is being published to elicit reactions to the modules finished so far.]