Students of Wittgenstein's philosophy often claim that the only work that Wittgenstein authored and published during his lifetime was the Tractatus Logicus–Philosophicus (German 1921, English 1922), and rarely mention a dictionary he composed for school children in 1926 during the years he spent as a schoolteacher in Austria. The reason for this neglect might be that this period of his life has been considered a lost period, in which he did not produce any work of philosophical significance after the Tractatus. This study sheds light on the six years that Wittgenstein spent as a schoolteacher and examines their impact on his intellectual transformations. By exploring the probable connections between his experience as a teacher and his later philosophy, the study considers his experience in teaching as a key to understanding his rejection of logical positivism and his turn toward a philosophy centered on practice, use and norms. Wittgenstein's later works, such as Philosophical Investigations, the Brown Book, Zettel, and On Certainty, are replete with examples and thought experiments that refer to the process of teaching and learning, e.g., how a child learns a language or performs mathematical operations. The abundance and frequency of these examples in various contexts indicates that they are not arbitrary, but rather show the centrality of teaching and learning in Wittgenstein's anthropological philosophy. The study includes an Arabic translation of the preface Wittgenstein wrote for his Wörterbuch.