With several other Mortimer Keene books published, fans may be pleased to see this latest instalment of Mortimer Keene’s rhyming adventures. In this episode, he and his entire school are unwittingly transported back to the time of the dinosaurs by a collision between an errant marble and a time machine. Can Mortimer’s zany inventions save his friends from fierce dinosaurs and get everyone back to the present day? Of course they can, but the doing of it is great fun, and there’s a pleasing twist at the end when Mortimer’s friend brings back a souvenir. Entertainingly told in rhyming verse throughout, and with several appendices illustrating the time machine and a variety of dinosaur facts, this is an enjoyable read for youngsters aged 5 and up. It may be helpful for younger readers to have the text read aloud before reading independently in order to tackle some tricky dinosaur names and read the text with rhythm, but the format of the book, illustrations and page layout make it suitable for independent reading in this age group.