Pyrrhus et Cinéas and Pour une morale de l'ambiguïté constitute Simone de Beauvoir's early philosophical works, prior to the publication of Le Deuxième Sexe in 1949. Yet, until relatively recently, most critics have tended to regard them as derivative of Sartre's L'Etre et le néant. Such a stance, which negates Beauvoir's independent contribution to the development of existential phenomenology, is increasingly hard to justify. In this chapter, it will be evident that Beauvoir goes beyond slavish reproduction of ideas in L'Etre et le néant, not only displaying broad knowledge of the sources of existential phenomenology, but also distancing herself from certain Sartrian notions of freedom, action, corporeality and intersubjective relations. Space constraints preclude a complete analysis here of the divergences in Beauvoir's and Sartre's philosophical trajectories in the 1940s, let alone across the broader spectrum of their careers. Instead, this chapter and Chapter 2 focus on Beauvoir's notion of selfhood in Pyrrhus et Cinéas, Pour une morale de l'ambiguïté and Le Deuxième Sexe, in the context of Sartre's L'Etre et le néant and Merleau-Ponty's Phénoménologie de la perception (1945) because, as Sonia Kruks and Toril Moi have noted, both these texts are important for Beauvoir's development of her own notion of subjectivity as a situated freedom in the world.