The paper presents and discusses the main results of Joint Commitment. How We Make the Social World, the book published by Margaret Gilbert in 2014. The author presents and defends her plural subject theory: against methodological individualism she shows that joint commitment can create a plural subject which is irreducible to its own parts. This idea, already presented in previous books of the author, is discussed dealing with new interesting topics such as collective guilt feelings, love, patriotism. The final section of the paper stresses some of the stengths of the book and shows also some of its weaknesses, such as the need of a discussion of joint commitment within a phenomenology of social stances.