'Though I sang in my chains like the sea.' This may be one of Dylan Thomas's most famous lines, but how many know that it is an example of cynghanedd, one of the world's oldest verse forms? And that that verse form is a uniquely Welsh one? Cynghanedd means harmony, and it is the music of Welsh poetry throughout the ages that Mererid Hopwood celebrates in this accessible handbook. Originally published in 2004, this new edition with a Foreword by Professor M. Wynn Thomas includes refinements which take into account some of the developments in the poetry scene in Wales over the last decade, not least the new formats it has found on social media. Professor Mererid Hopwood is one of Wales's most popular and highly respected authors, not least because of her exploits at the National Eisteddfod, where she has won all three of the major literary prizes, namely the Chair, the Crown and the Prose Medal. A former Children's Poet Laureate of Wales, she is also much in demand as a lecturer, creative-writing tutor and broadcaster.