In this panoramic novel of Friar Roger Bacon, John Cowper Powys displays his genius at its most fecund. First published in 1956, this novel, set in thirteenth-century Wessex, is an amalgam of all the qualities that make John Cowper Powys unique.

The love-story of Lil-Umbra and Raymond de Laon, and the quest of the Mongolian giant, Peleg, for Ghosta, the girl seen, loved, and lost on the battlefield, are intermingled with the historical, theological and magical threads which form the brocade of this novel.

Dominating all is the mysterious creation of Roger Bacon one of the boldest as well as most intricate of Powys' world-changing inventions. Professor G. Wilson Knight called this 'A book of wisdom and wonders'.