In this paper I will give a systematic account of Husserl's notion of the natural attitude in the development from its first presentation in Ideas I (1913) until Husserl's last years. The problem of the natural attitude has to be dealt with on two levels. On the thematic level, it is constituted by the correlation of attitude and horizon, both stemming from Husserl's theory of intentionality. On the methodic level, the natural attitude is constituted by three factors: naturalness, naivety and normality. I shall conclude by sketching out a possible motivation for leaving the natural attitude and thus for entering the sphere of phenomenology.