The seminal work on Owain Glyn Dŵr’s history is Professor Sir R.R. Davies’ The Revolt of Owain Glyn Dŵr published by Oxford University Press. 1997. ISBN 0-19-285336-8. The late Professor Davies was Chichelle Professor of History at All Souls College, Oxford and was the universally acknowledged authority on Owain Glyn Dŵr and his history.
Professor Davies is the author of a very accessible book aimed at the general reader
Owain Glyn Dŵr - Tywysog Cymru that is available as an excellent translation by Gerald Morgan called Owain Glyn Dŵr - Prince of Wales, published by Y Lolfa. 2009. ISBN 978-1847711274.
Another readable, brief but authoritative work is that of Professor Glanmor Williams, Owain Glyndŵr, published by the University of Wales Press. 1993. ISBN 0-7083-1193-8.
Other books giving interesting insights into his campaign are:
Owain Glyndŵr – A Casebook, ed. by Michael Livingston and John K. Bollard.
Liverpool University Press. 2013. ISBN 978-0-85989-884-3.
Dyddiau Olaf Owain Glyndŵr, Gruffydd Aled Williams. Y Lolfa. 2015. ISBN 978-1-78461-156-9.
In Search of Owain Glyndŵr, Chris Barber . Blorenge Books. 2004. ISBN 1-87-2730-33-7.
Owain Glyn Dŵr & the War of Independence in the Welsh Borders, Geoffrey Hodges.
Logaston Press. 1995. ISBN 1-873827-24-5.
Glyn Dŵr’s War, G. J. Brough. Wales Books Glyndŵr Publishing. 2002. ISBN 1-903529-069.
The Rise and Fall of Owain Glyndŵr, Gideon Brough. I.B. Taurus. 2017. ISBN 978-1-78453-593-3.
Glyndŵr’s First Victory – The Battle of Hyddgen 1401, Ian Fleming. Y Lolfa. 2001.
ISBN 0-86243-590-0.
Owain Glyndŵr – The Story of the Last Prince of Wales, Terry Breverton. Amberley. 2009.
ISBN 978-1-84868-328-0
The Mystery of Jack of Kent & the Fate of Owain Glyndŵr, Alex Gibbon.
Sutton Publishing. 2004. ISBN 978-0-7509-3320-9.
Glyndŵr’s Daughter, John Hughes. Y Lolfa. 2012. ISBN 1847713319
The classic work on the subject until the advent of R.R.Davies was:
Owen Glendower, J.E. Lloyd. Oxford University Press. 1931. View Biography
The following works are very accessible accounts of Welsh history:
A Brief History of Wales, Gerald Morgan. Y Lolfa. 2008. ISBN 9781847710185.
A History of Wales, John Davies. Penguin Books. 1990. ISBN 0-14-012570-1.
A Brief Bibliography
A. G. Bradley, Owain Glyndŵr and the Last Struggle for Welsh Independence. 1902.
J. D. G. Davies, Owen Glyn Dŵr. 1934.
Gwynfor Evans, Land of My Fathers, 1974.
E. F. Jacob, The Fifteenth Century. 1961.
G. A. Jones, Owain Glyndŵr. 1962.
R. H. Jones. The Royal Policy of Richard 11. 1968.
J. L. Kirby, Henry 1 of England. 1970.
J.E. Lloyd, Owen Glendower. 1931.
T. Mathews, Welsh Records in Paris. 1910.
M. McKisack, The Fourteenth Century. 1959.
T. J. Pierce, Medieval Welsh Society. I1972.
D. R. Phillips, A Selected Bibliography of Owen Glyndŵr.
W. Rees, South Wales and the March, 1282 - 1415. 1924.
I. Skidmore, Owain Glyndŵr, Prince of Wales.
J. A. Tuck, Richard 11 and the English Nobility. 1973.
G. A. Williams, When was Wales. 1985.
The National Library of Wales, Aberystwyth has a very extensive collection of books and documents on Owain Glyn Dŵr’s history.