The Black Cloud

Ah, more 50's Sci-Fi - but this was different. Written by a renowned Cambridge astrophysicist it's heavy on the science and its fiction is based on facts.
A sentient alien cloud blocks the Sun's light to Earth and a group of scientists attempt to survive in a country house. They manage to make contact with it and exchange information before the cloud has to continue its mission.
There are some beautifully written characters and the debates between the scientists are most entertaining. It's a bit short on “action” and the large-scale death and destruction is mostly a footnote. This makes the final, more personal, deaths quite unexpected. And then it ends. It left me a bit deflated, to be honest, but in a good way.