With his first book, Itch, Simon Mayo introduced science-mad Itchingham (Itch) Lofte, whose passion for collecting every element he could caused all sorts of strife when he acquired rocks of a previously unknown radioactive substance.
At the end of his first book, it was difficult to see how Mayo could move forward, but with Itch Rocks he shows how much smarter he is than the sceptics.
Rather than have his rocks fall into the hands of his former science teacher, the thoroughly nasty Dr Flowerdew, Itch hides them in a deep well and refuses to tell anyone where he put them.
That resulted in the boy, his sister Chloe and cousin Jack becoming the most protected youngsters in English history.
But even that doesn't stop various groups trying to wrest Itch's secret from him.
As in the first book, Itch Rocks has lots of interesting science: for instance, when Itch puts tellurium (Te) in Dr Flowerdew's whisky and later, the teacher gives away his hiding place by his appalling body odour.
There's a very satisfactory ending and if at times during the book the information on various chemical reactions seems a bit overdone, it's all genuine stuff, making Itch Rocks perfect for those aged about 12 and up, especially boys, with a scientific bent.
David's Great-uncle Felix, a writer of children's books set in a land called Axillaris, comes to stay.
David's brother, Gray, is unimpressed, especially when he discovers that the hero of the Axillaris books it called Felix.
''What a bighead,'' he scoffs. Then strange things start happening, beginning with Gray's white rats turning red.
Meanwhile, David is re-reading his favourite Axillaris book - reproduced between the present-day action - and it slowly dawns on him that it is not fiction but an account of Felix's genuine experience.
But what is the significance of the red rats?
An entertaining novel for readers aged 10 and above.
Walking the fine line between keeping the language straightforward without being over-simplistic, Gilderdale presents a lively picture of Mahy, who died in July 2012.
Just how important Mahy was is illustrated by the appendices, one a staggeringly long list of her published work, the other of the numerous awards she received.
From A Lion in the Meadow (never out of print since first released in 1969) to Footsteps Through the Fog (2012), she has left an enduring legacy that, incidentally, demonstrates that a New Zealand author need not be consciously ''Kiwi'' in approach.
The beauty of this little book is that adults will enjoy it as much as Mahy's many younger fans although, that said, there is clearly a place for a full-scale biography of the writer.
Judging by Magical Margaret Mahy, Gilderdale could well be the person to tackle such a project.
