This paper examines the concept of the world elaborated by Heidegger in the early Freiburg lecture courses of the years 1919 to 1923, in which he proposes a renewed conception of phenomenology through a comparison with Husserlian phenomenology. First, I show that although the theme of the lifeworld became central only in late Husserlian works, especially in _The Crisis of European Sciences_, Husserl began to deal with this concept before 1920, anticipating some fundamental issues of the _Crisis_, as it results (...) from the lectures of 1919 on _Natur und Geist_. Husserl had addressed the concept of the world already in the lectures of 1910/11, _The Basic Problems of Phenomenology_, and, subsequently, in the second book of _Ideas_, which was published posthumously, but which was known to the young Heidegger. Then, I discuss the way in which Heidegger revisited the issue of the world in the early Freiburg lecture courses by means of a critique of Husserl’s analysis, focusing on perceptual experience as “environmental experience” and on the “world-character” of life. Particular emphasis is placed on the distinction between “environing-world,” “with-world,” and “self-world,” which Heidegger introduces in the lectures of 1919–1920. Finally, I point out that the Heideggerian rethinking of the concept of lifeworld is closely connected to the recognition of the immanent historicity of life, while Husserl only later takes into account the historicity of the lifeworld. (shrink)