From The Telegraph:
The beginning of a joint book by CS Lewis and JRR Tolkien has been discovered in a manuscript book in the Bodleian Library, Oxford.
An American academic called Steven Beebe, of Texas State University, San Marcos, had seen the material some years ago, but has only recently realised what it is. It is written in Lewis’s hand in the same notebook that contains early drafts for The Voyage of the Dawn Treader and The Magician’s Nephew.
Lewis and Tolkien had planned their joint book, to be called Language and Human Nature, in 1944, with publication envisaged for 1950.
Apart from the difficulty that Tolkien had in finishing any book, the timing of the joint venture was not propitious, for Tolkien felt that Lewis and he were “separated first by the apparition of Charles Wiliams”. Williams had joined meetings of the Inklings on being evacuated from London during the Second World War. He died in 1945, but the damage to the relationship between Lewis and Tolkien had been done.
Still, they retained a friendship and exchanged ideas. Tolkien had strong notions of the relation between language and myth. Lewis said something about the development of language within cultures in Studies in Words, published in 1960.
In the newly identified manuscript, Lewis writes as “we”, and it will be interesting to see how far Tolkien’s thought enters into the argument.