Superb sci-fi novel in the same strain as Welles's War of the Worlds, Abe's Inter Ice Age 4 and Wyndham's own Day of the Triffids.
The Kraken Wakes is more political and, with its journalist main characters (they can hardly be called protagonists - the protagonists are the 'bathies', the things that live in the Deeps) and its constant updates on what all the papers and radio stations are saying, is a satire on the media, and the media's reaction to crises - and also how a single event can can be interpretted and, more importantly, presented in countless, differing lights.
In the continual public rejection of what Bocker, the genius scientist who always correctly predicts what the bathies are going to do next and says it like it is, it's a particular satire on our tendency to ignore and deny crises. In 'Phase 3' (the book is divided into three 'phases') this bears a striking parallel with modern day climate change, as ice caps melt and sea levels rise, threatening to drown the world.
In its drowned world section The Kraken Wakes blows Ballard's Drowned World out of the water.
There's something at the end which smacks slightly of selling out, but even this is nearly acceptable, though it does go against the book's presiding current of doom and inevitable loss.
I wonder why this book never became as famous as the Triffids or why it has never been adapted for film or television. Its world-spanning description of the slow, spectacular and terifying extermination of the human race by an unknown alien force is fantastic dramatic fare.