The Blue and Brown Books are two sets of notes taken during lectures conducted by Ludwig Wittgenstein from 1933 to 1935. They were mimeographed as two separate books, and a few copies were circulated in a restricted circle during Wittgenstein's lifetime. The lecture notes from 1933–1934 were bound in blue cloth, and the notes dictated in 1934–1935 were bound in brown. Rush Rhees published these together for the first time in 1958 as Preliminary Studies for the "Philosophical Investigations". Inchoate versions of many of the ideas that would later be more fully explored in the Philosophical Investigations are found there, so these offer textual evidence for the genesis of what became known as Wittgenstein's later philosophy. The Blue Book The Blue Book was dictated from 1933 to 1934, and contains certain themes unaddressed in Wittgenstein's later works, including deliberations on thinking as operating with signs. An early conception of what would later become known as language-games is present in the text, which represents the first period of Wittgenstein's thought after 1932, a method of linguistic analysis which would later become ordinary language philosophy. While Wittgenstein in The Blue Book is not dogmatic nor systematic, he does provide arguments that point toward a more self-critical view of language. For example, he does not think that "understanding" and "explaining" are necessarily related. He suggests that when humans are learning a language-game they are actually being trained to understand it. He writes: As the citation suggests, Wittgenstein views understanding a language-game as being mostly concerned with training (which he calls "drill[ing]" in the above citation). Having said that, Wittgenstein is not one to believe that even understanding a language-game can be reduced to one process; like the plethora of language-games available to human beings, there are also plethora of "understandings." For example, the "understanding" of a language may come about by the "drilling" of the association between the word "yellow" and a yellow-patch; or it may involve learning rules, like rules used in the game of chess. Moreover, Wittgenstein doesn't think that humans use language mechanically, as if following a calculus. He writes in The Blue Book, "[I]n general we don't use language according to strict rules—it hasn't been taught us by means of strict rules, either." Wittgenstein clarifies the problem of communicating using a human language when he discusses learning a language by "ostensive defining." For example, if one wanted to teach