Magnet of Doom by Georges Simenon

Published in French in 1947, this English translation was published by Pan-Books in 1956. The imprint page is missing from this copy so I do not have further details. 

The Strangers in the House by Georges Simenon

First published in French in 1940, this translation was published by Digit Books, London, 1962.

The Magician by Georges Simenon

This English translation was published in 1956 by Berkley Books, USA. 

Illustrated book covers: Georges Simenon's Mr Hire's Engagement

Mr Hire's Engagement by Georges Simenon, first published in French in 1933. Translated into English in 1956, this edition by Arrow Books was published in 1958. 

Illustrated book covers: Georges Simenon's Maigret's Little Joke

First published in France in 1957 as Maigret s'amuse. Published in English by Arrow Books in 1961; this copy is the second edition from 1963.