An omnibus edition of Fisk's 1973 novel "Grinny", and its 1984 sequel "You Remember Me".

The first book tells of a sinister old woman, nicknamed "Grinny", who poses as a relative and embeds herself with an English family. She turns out to be an alien cyborg laying the groundwork for a hostile takeover of the human race. She is able to control the minds of adults, but it is up to the children of the household to thwart her.

The book is short, even by the standards of children's fiction, and I think Fisk skimps on the logistical requirements of science fiction. There's almost no attempt at a scientific explanation for the children's ability to fight off this advanced alien invader. Young readers deserve better than this, no less than us adults. I don't think I'm being old and cynical. I am a lifelong consumer of children's fiction - I simply never grew out of it - and I think my standards of judgement are fair.

The strengths of this little novel lie elsewhere. The creation of an evil entity in the form of a senior citizen reminds me of the generational changes of the times, following the 1968 student uprisings as young people sought to break the stranglehold of previous generations who had made such an appalling mess of the 20th century up to that point. The nice kindly old lady is no longer credible - the older generation is a MENACE!

The portrayal of family life is vivid, as the more relaxed mores of the late 60s and early 70s are disturbed by the leering old Grinny. Fisk also experiments with narrative technique, with most of the book in diary format, and he even introduces himself as a character.

The sequel is a surprising evolution. An upgraded mind-controlling alien returns, this time in the form of a right-wing populist demagogue. Even older teens are susceptible to her hypnosis, as the entire nation joins a mass movement which might well have the slogan "Make America Great Again" if the story were set in the USA. The echoes of our real-life political malaise of the past decades are all too strong, with zealous zombie-like hordes waving union jack flags and slavering over concepts like "discipline" and "rule of law". Margaret Thatcher is referenced, not by name, but with her memorable quote "the lady's not for turning".

Once again Fisk writes himself into the story and, marvelously, portrays himself as a fully vanquished devotee of the neo-fascist alien overlord - until the resourceful child heroine wins the day and frees his mind.

As in the previous novel, the weapons wielded by our planet-saving pre-teen protagonists strain the suspension of disbelief. I am reminded of "The Andromeda Strain" and the dreadful movie of "The Day of the Triffids", both of which included the discovery that seawater was the secret weapon to fight off the otherwise all-powerful monsters. Puh-lease. But it matters less here, because "You Remember Me" is a early warning of the lingering threat of tyranny in human affairs, and another smash hit from the esteemed author Mr Fisk.