In this authoritative book, Richard Wyn Jones traces the development of the political thought of Plaid Cymru from its birth in the winter months of 1924–5 to the establishment of the National Assembly for Wales in the summer of 1999. With a penetrating study of the political beliefs of Plaid Cymru’s most important leaders – Saunders Lewis, Gwynfor Evans, Dafydd Elis-Thomas and Dafydd Wigley – Wyn Jones charts the party’s emergence from the political fringe to the threshold of a devolved Wales. The development of the party’s constitutional and economic policies is given close attention, as well as its attitude towards the Welsh language; and from a vibrant discussion on the nature of nationalism and nationalist ideas, Plaid Cymru’s intellectual development takes its place within a broader historical and international context. The result reveals Plaid Cymru in a new and sometimes controversial light.