One method that some businesses used to control union activity was the yellow-dog contract between worker and owner or management. A yellow-dog contract is an agreement between an employer and an employee in which the employee agrees not to join a union or participate in union activities as a condition of employment. These types of contracts were often used by employers to prevent workers from organizing and collectively bargaining for better wages, benefits, and working conditions. The practice of using yellow-dog contracts was outlawed by the Norris-La Guardia Act of 1932, which protected workers' rights to join unions and engage in collective bargaining.