William J. Dowler CPA Overview William J. Dowler, CPA is a leader in income tax preparation and accounting services for individuals and small businesses. We prepare over 1,300 individual income tax returns and over 200 business and excise tax returns annually. We utilize our expertise to provide solutions and innovative ideas to help guide our clients to financial success.   We are located in East Islip, NY providing services to a variety of businesses and individuals on Long Island and throughout the country. We are devoted to providing the highest quality of service.