Five best books on labor unions

Richard B. Freeman holds the Herbert Ascherman Chair in Economics at Harvard University.He recommended a few books on labor unions to Eve Gerber at FiveBooks, including:Exit, Voice, and Loyalty: Responses to Decline in Firms, Organizations, and StatesAlbert O. Hirschman[Gerber:] Your work seems greatly influenced by that of economist Albert O Hirschman. Can you please expound on the theory put