Do other people limit or even threaten our freedom and our projects, or are they necessary to their realisation? Do we only answer to ourselves for our actions, or are we accountable to other people as well, and if so, to whom? Do we have a responsibility for the welfare of other people? These questions, which Beauvoir addressed in the works she wrote from the Second World War onwards, have lost none of their relevance. Chapter 3 explores them by analysing many of her works, including The Ethics of Ambiguity, Pyrrhus and Cineas, America Day by Day, and her novels The Blood of Others and The Mandarins, which focus on social responsibility, communal action, and groups. Her anti-individualistic concept of freedom, focussed on projects and solidarity, is contrasted with the so-called negative concept of freedom and versions of the liberal concept of freedom. Beauvoir’s concepts of freedom, solidarity, and responsibility are proposed as tools to reflect on current issues, including some uses of social media, assisted suicide, the environment, and what should be done about historical wrongs such as slavery.