This lecture is an introduction to J.R.R. Tolkien's third major work, 'The Silmarillion' (1977), and considers its lengthy development in numerous prose and verse texts over fifty years. This lecture offers a guided tour through the development of J.R.R. Tolkien's 'Silmarillion' corpus, inclusive of The Silmarillion (1977) and the earlier versions of the same work published in the History of Middle Earth series (1983-1996). The most mythological and magisterial of Tolkien's major works, the 1977 Silmarillion (and its antecedents) gives the reader a very different experience and perspective than his more famous and widely read works, The Hobbit (1937) and The Lord of the Rings (1954-1955). A mythology in the true sense, the 'Silmarillion' corpus is peopled with gods and other preternatural beings and represents the earliest comprehensive work of Tolkien's imagination. Since it was begun in earnest in the middle of the First World War, one of the most turbulent periods in modern history, its tone is more sober and its events more tragic than those of his other classics, but its powerful messages of nobility in the face of defeat and courage in darkness resonate with the world events of the time in which it was produced.