"Engage the grey cells with Wilfred and Olbert. Packed with puzzles, this book can be enjoyed over and over again." -- Little London "An unusual and enjoyable way to encourage children to explore the world of prehistory and a great way to spark an interest... An engaging book with plenty of humour to keep the interest high." -- Parents in Touch "A fantastic journey of discovery...youngsters can enjoy lots to spot, learn fascinating facts, and solve puzzles." -- Lancashire Evening Post "Frenetic, crazy, action-packed and bursting with speech bubbles: search-and-find enthusiasts especially, will quickly be sucked through the portal along with Will and Ollie, taking a considerable time to emerge from this absorbing book." -- Jill Bennett / Red Reading Hub