Jakobson was a leading, original figure at the forefront of the promotion of semiotics in the international arena - paving the way for the developement of this unique and emerging discipline. Among the many valuable insights he envisaged in his Selected Writings, this paper focuses on the notion of the nature of signs and seeks to provide a comphehensive outline of this perspective of both signs and sign-typologies. What was the concept of the sign Jakobson subscribed to? And what are its roots? What were the main sources he drew on? The paper aims at systematizing Jakobson's thought and pinpoint his legacy to semiotics - with particular reference to his distinctive theoretical viewpoint on signs.