An expert system called TARA, for Technical Analysis and Reasoning Assistant, has been built and deployed to assist foreign currency traders in their decisions to buy, sell, or hold market positions. Trading with the system began in May, 1988. Since then, TARA has paid back all of its development costs plus an attractive return on investment. This achievement represents a major breakthrough for Al in financial services. Trading is a high risk, high reward profession that at first glance appears unsuitable for an expert system solution. The knowledge is fuzzy, no two experts seem to agree and, for a system to offer significant benefit, a large volume of data must be analyzed in real time. TARA’s success demonstrates that expert systems technology can be effective in the financial trading environment.