The following is not a review but verbatim blurb from the dust jacket of the 1951 Heinemann first (only) edition of 'Constancy' by Phyllis Paul:
"This is a story of constancy and devotion; it is a story of that determination to sacrifice self which, feeding upon itself, grows from strength to strength until it dominates the mind in which it is implanted.
How youthful and fragile was Miss Paul's heroine when the fiancé whom she hardly even knew, and certainly did not love, broke down on his visit to her and was immured for long years in a mental home! Yet she, who was clearly on the point of ridding herself of him for a better match, suddenly decided to row in with his ineffectual family and assume responsibility for his welfare. Thus she sacrificed her best years to pay the expenses of this man to whom she owed nothing.
The years slipped by. In the dim outside world of reality, peace gave way to war, and war once more to peace; and "reconstruction" meant little to the burdened mind of the woman whose youth was now lost... until murder set her free.
To say that murder brings drama to this story would be ridiculous, because it is dramatic at every turn. Miss Paul's writing is inescapably dramatic. She has only to follow one of her characters the length of a poor street at night for the very shadows to be fraught with mystery and threat.
Yet this power of atmospherics is the most incidental of her gifts. It is her portraits of the inner life of her characters which finally obtrude in her pages. Take for instance that parallel case of constancy, the case of the young man of warped body and devious mind, whose picture brings more than a touch of humour to a novel rich in characterisation, and expressed in prose of truly fine quality."