A professional corporation is a variation of the corporate form available to entrepreneurs who provide professional services—such as doctors, lawyers, accountants, consultants , and architects. "Professionals," Frederick W. Dailey explained in his book Tax Savvy for Small Business, "are treated as small businesses under the tax code. Most of them operate as sole proprietorships or partnerships, and are subject to the same tax rules as other similar businesses. However, certain professionals who offer services may form and operate a special type of entity, called a professional corporation." Some states require professionals to form this type of entity if they wish to incorporate. In a professional corporation, the owners perform services for the business as employees.