Abstract The Knights of Labor, the first national industrial union in the United States, was founded in Philadelphia on December 9, 1869, by Uriah Stephens (1821-82) and eight other Philadelphia garment cutters. Intended to overcome the limitations of craft unions, the organization was designed to include all those who toiled with their hands. By mid-1886 nearly one million laborers called themselves Knights, making the organization the largest and most influential labor union in nineteenth century America. Stephens aspired to unite all wage-earners into a single organization regardless of skill, race, or sex. The organization excluded liquor dealers, lawyers, bankers, and professional gamblers. Stephens stressed the importance of solidarity within the ranks of labor in order to meet the power of capital. Between December 1869 and April 1875 the Knights made few gains outside of the city. During that time eighty-five local assemblies were established, seventy within the Philadelphia region. After the Great Railroad Strike of 1877 membership expanded and the first national officers were initiated after a convention in Reading, Pa., in 1878. In 1879 Terence V. Powderly (1849-1924), a native of Carbondale, Pa., replaced Stephens as Grand Master Workman after Stephens resigned the position. Powderly, who also served as the socialist mayor of Scranton from 1878-84, led the Knights until 1893. This study includes an introduction, four chapters and a conclusion, chapter I dealing with The roots of the labor movement in the United States of America until 1866 , This chapter dealt with a number of topics which are as follows: the first topic the labor movement in the colonial era, the second topic the factors crystallization of the labor movement after independence 1783-1840, and the third topic union activity until the end of the American Civil War 1840-1865. As for the second chapter, which was titled: The Emergence of the Workers' Organization and its Role in the Workers' Movement until 1881, it dealt with a number of topics which are as follows: The first topic is the general scene of the labor movement before the formation of the Workers' Organization 1866-1869, and the second topic is the principles and structure of the Workership Organization, the topic The third activity and work position of the Knights of the Economic Crisis 1870-1879, the fourth topic, Terence V. Powderly and his role in the development of the organization 1879-1881. The third chapter came under the title: The Rise and Prosperity of the Workers ’Organization 1881-1886, which dealt with a number of topics, as follows: The first topic: The factors of the rise of the Workers’ Organization, the second topic: the organization’s position on black workers, the third topic the organization’s activity in the southern states, the fourth topic position The organization from the strike of 1885-1886 and its reflection on the increase in membership, Section Five the organization's position on political action. Finally, the fourth chapter came under the title, Factors of Weakness of the Labor Knights Organization and its Decline 1886-1895. A number of topics were discussed as follows: The first topic: Organizational and structural problems within the Labor Knights Organization, the second topic is the repercussions of the failure of strikes on the organization in 1886-1887, the third topic is the position of the Knights on the Haymarket case And its negative repercussions, the fourth topic: internal differences and divisions and its role in the weakness of the organization, the fifth topic: the end of the Terence V. Powderly era and the decline of the organization's role in the labor movement.