All four titles in Barbara Nadel’s shorter (and probably lesser known) Francis Hancock series have dropped to £0.99 each at Kindle UK. The titles include:
And the second one, After the Mourning, has been semi-long-term at $1.99 in the US.
Buy Last Rights, #1, at Kindle UK
Buy After the Mourning, #2, at Kindle US | Kindle UK
Buy Ashes to Ashes, #3, at Kindle UK
Buy Sure and Certain Death, #4, at Kindle UK
All four books are now $0.99 each at Kindle US. Here is a link for the series webpage: https://www.amazon.com/dp/B077L6JB5R?binding=kindle_edition