By Paul French, one of the most famous Science Fiction writers of all time. Admittedly written during a time when Venus was still a relative unknown, this book's Venus has a single global Ocean of carbonated water...I couldn't stop imagining dumping a tanker full of Mentos in that...where men live underneath the waves in fantastic domed cities cultivating advanced yeast cultures for food and export.
David Starr volunteers to investigate strange rumors of trouble brewing on Venus. Together with his sidekick, the Martian John Bigman Jones, they have hardly descended into the perpetual Venusian cloud cover when they are attacked by forces-unknown.
The story has our hero battling human controlled mind-controlling aliens controlling humans (let that simmer a bit and you'll get what I mean). The ending seems a bit weird for such a light story though; Starr decides that the mind controlling technique of the villain could be of some use to the Scientific Council which even I ( epimethean that I am) don't think sounds very prudent. I mean if one man was corrupted by that power, what would the possession of that ability do to a council of men who are supposed to be on a Cold War footing against another group of humans in Sirius.
Regardless, this is vintage juvenile science fiction. Very good stuff.