In the book, the authors extend Nash's ideas on bargaining to deal with situations where the number of people involved can change. They establish rules to guide solutions in these shifting scenarios and explore different solutions in light of this variability. The classic bargaining theory remains strong, with Nash's, Kalai-Smorodinsky's, and egalitarian solutions standing out. The work sheds new light on how bargaining solutions adapt when the number of participants is not fixed, showcasing the importance of these three main solutions in diverse bargaining situations.