As well as being a noted litterateur, D.J. was one of Wales' most important nationalists during the twentieth century. He steadfastly believed that Wales should be given the political powers to run itself, without interference from the British Empire. He devoted his life to realising his dream of seeing a free Wales by working tirelessly on behalf of Plaid Cymru and he attempted to present his vision to contemporaries through his articles and litterary works. The source of inspiration, that supported him through years of tireless struggle, was his ideal of establishing in Wales a nation based on the idealistic childhood that he experienced in Rhydcymerau. He left Rhydcymerau at just sixteen years of age and lived in exile in Fishguard for fifty years. Perhaps this banishment made D.J., the Giant of Rhydcymerau, one of his nation's greatest. This is the first comprehensive biography on the life and work of this remarkable Welshman, and sees the publication, for the first time, of extracts from his diaries.