In the late 19th century, baseball players broke from the established leagues and organized their own Players' League. They believed that this rival organization would make wages subject to market conditions and give players more mastery over their careers and industry. Although the league lasted only one year, it was a significant attempt by skilled workers to break from an established monopoly, gain more control over all aspects of their industry, and reap a larger portion of the revenues that they created. This work explores the early history of professional baseball in the United States, the factors that contributed to the player rebellion of 1890, and the rebellion's impact on the player-owner relationship in the decade that followed. Appendices include a roster of the 1869 Cincinnati Red Stockings (players, positions, and salaries); the First Reserve Agreement, Section 18 of the Standard Player's Contract; and commentary and legal documents pertaining to the Reserve Rule.