| They Never Say When | |
| Author: | Peter Cheyney |
| Country: | United Kingdom |
| Language: | English |
| Series: | Slim Callaghan |
| Genre: | Thriller |
| Publisher: | William Collins, Sons |
| Release Date: | 1944 |
| Media Type: | |
| Preceded By: | Sorry You've Been Troubled |
| Followed By: | Uneasy Terms |
They Never Say When is a 1944 thriller novel by the British writer Peter Cheyney.[1] It is the sixth in his series of novels featuring the London private detective Slim Callaghan, a British version of the increasingly popular hardboiled American detectives.
Callaghan is hired by a Mrs Paula Denys who claims that she paid a to steal a priceless coronet from her husband's safe. Now he refuses to hand over the stolen and is instead trying to blackmail her.