In the novel Mrs McGinty’s Dead, Maureen Summerhayes is the landlady of the dilapidated guesthouse Long Meadows in Broadhinny who is married to Major Johnnie Summerhayes. She was adopted. Mrs McGinty was her cleaner, and went to Long Meadows twice a week--on Mondays and on Thursdays.
Mrs Summerhayes has red hair and an "attractively freckled face". With her husband, Maureen had recently arrived from India where they used to have many native domestic servants. Bessie Burch mentioned how Mrs Summerhayes was a sympathetic woman, but "didn't know a thing about a house". The married couple tried to market-garden, but did not succeed in that either.
While boarding at Long Meadows, Hercule Poirot gives her a cookery book and teaches her to make omelette.
Just like James Sheppard in The Murder of Roger Ackroyd before her, she believes Poirot is a retired barber. She is quite sure that James Bentley killed Mrs McGinty. When Poirot tells her he is a private investigator, she jokingly asks him if he investigated about cigar ashes and fingerprints. In Long Meadows, Poirot finds the picture of a murderer with the words 'My mother' written in the back of it. It later turns out someone had placed that there to make suspicion fall on Mrs Summerhayes.
Mrs Summerhayes was portrayed by Raquel Cassidy in the ITV TV adaptation of the novel, for the TV series Agatha Christie's Poirot. Here she goes to Laura Upward's house the night she was murdered but finds it empty and leaves. In the original novel this was done by Deirdre Henderson, which is omitted in this adaptation.