When I was a boy I collected and devoured - yes devoured - all the Target 'Doctor Who' novelisations. My teachers despaired of me reading anything else. And there were some books in the series that I read and re-read. This was one of them. It's vintage Terrance Dicks, bless him. Simply written with children in mind, but brilliant nevertheless. All the things I love most about 'Doctor Who' are here - the fourth doctor at the height of his powers, Sarah and Harry as his faithful companions, a spooky, fog-bound location and great supporting characters (who can forget the pub landlord with second sight or creepy Nurse Lamont or the homicidal 'Caber'?). And did I mention the Zygons, one of the best monsters ever to grace the series? In fact isn't it about time they made a return? They're too good to be one hit wonders.