The hours before dawn - Celia Fremlin

The Hours Before Dawn (1958) was Celia Fremlin's debut fiction, and won the Edgar Award for novel of the year from the Mystery Writers of America. Over time Fremlin would earn the soubriquet of 'the mistress of psychological suspense.'

Louise
Henderson is a young housewife and mother, trying her best to tend to a
husband, two small daughters and a constantly crying baby. Her fatigue
is such that she fears she is nearing psychosis; and she can't help
but feel that a new lodger in the house, a seemingly respectable
schoolmistress, poses a threat to her and her family.

'Tightly plotted and admirably concise... Fremlin expertly ratchets up the tension, notch by notch.' Laura Wilson

'Highly intelligent entertainment, beautifully written with wit and humour.' Frances Fyfield

'It grips like grim death.' Spectator