Mignon Good Eberhart
An American author of mystery novels. She had one of the longest careers (from the 1920s to the 1980s) among major American mystery writers (<a href=https://en.wikipedia.org/wiki/Mignon_G._Eberhart>Wikipedia</a>).
Works (50)

Baker's dozen

The patient in room 18

Great Tales of Crime and Detection

While the patient slept

The mystery of Hunting's End

Unidentified Woman

The Glass Slipper

The dark garden

Family Fortune

R.S.V.P. murder

Five Passengers from Lisbon

Murder by an aristocrat

Mignon G. Eberhart's Best Mystery Stories

The Unknown Quantity

Melora

Two little rich girls

Call After Midnight

The white cockatoo

Witness at large

With this ring

Another woman's house

Hunt With the Hounds

Danger money
1975

Escape the night

Hasty Wedding

Patient in Cabin C

Murder in Waiting

A fighting chance

The house on the roof

Man Missing

El Rancho Rio

Next of kin

Wolf in Man's Clothing

Speak No Evil

Family affair

Three days for emeralds

Casa Madrone

Nine o'clock tide

The bayou road

Another man's murder

Postmark murder

The case of the irate witness; Two little rich girls; Gideon's art

Never look back

The cup, the blade, or the gun

Enemy in the House

Alpine condo crossfire

The Terrorists / Family Fortune / Maigret and the Apparition

Run Scared

Wings of fear

Message from Hong Kong