I was deeply underwhelmed by the TV version of this story, which fights off strong competition from The Web Planet to be probably the worst Hartnell adventure. Curiously, Nigel Robinson actually manages to smooth over the most awful bits of the narrative - the poor acting of the human characters, the poor characterisation of the non-humans - to the point where one feels that there is actually a decent sf tale in there somewhere, trying desperately to get out. Unfortunately the attempt is doomed to failure because of Robinson's plonkingly awful prose style. Some day some keen fan will do a version of this - the Sensorites as they should have been written. Meantime this book is only for completists.
I've already read the next book in sequence, Doctor Who - The Reign of Terror, one of Ian Marter's better efforts, so it's on to Terrance Dicks and Doctor Who - Planet of Giants next. Though I may stop off via The Witch Hunters.