ONE of the most celebrated marriages in modern literary history, the relationship between the author DH Lawrence and Frieda von Richthofen has long fascinated student and scholar, not least due to its tumultuous nature.

Frieda was the wife of Lawrence's former professor. Soon after meeting, the pair eloped to Bavaria, subsequently married and spent the best part of 20 years – if critics are to be believed – creating spectacular scenes in various countries as part of their nomadic existence.

Yet, as the author shows, theirs was a relationship based on great spirit, loyalty and commitment. Having gained access to hundreds of Frieda's unpublished letters, he reveals a powerful – but far from destructive bond.