ALCHEMY, a dangerous mix of magic and science, marked the beginning of chemistry in Europe in the Middle Ages. The alchemists of the day conducted experiments that terrified ordinary people and made them fear for their lives. Alchemists worked to discover three things. They wanted to invent a potion that would make humans immortal, they believed in the existence of the philosopher's stone that could turn ordinary metal into gold, and they dreamt of creating a homunculus, or tiny man. Martin Booth's spooky new novel, Doctor Illuminatus, mixes the weird theories of alchemy with a thrilling modern adventure story. Booth is an experienced adult novelist and non-fiction writer, and his first fantasy novel for younger readers is a fantasy with a difference. Doctor Illuminatus is a tale of real magic as opposed to fake spells and wizardry. All the magic here, the chants, the potions, the experiments really did exist. Booth cleverly brings them alive again in modern times as his 21st century hero and heroine get caught up in a sticky web of sorcery and betrayal. Twins Pip and Tim are unsure about moving to a big house in the country. Their new home, Rawne Barton, is a dilapidated 15th century manor house, many miles away from the nearest town. No one has lived there for ages, and the whole place is suffering from years of neglect. The twins have had no chance to settle down in their new surroundings when strange things start to happen. They hear knocking sounds in the wall between their two bedrooms and discover a secret door in the wood panelling behind Pip's bed. When they open the door, they are stunned to find the pale face of a young boy staring straight back at them. Pip and Tim can hardly believe the boy's story. He is 12 years old and was born in 1430. But he is no ghost. Sebastian Rawne is very much alive. His father, an alchemist at the court of King Henry V, had been burnt to death when he was 10. His enemies had turned on him and accused him of witchcraft. But before his father died, Sebastian had got his hands on a potion that put his body into a long sleep whenever he wanted. For the past 600 years he has been hunting his father's enemy, the evil De Loudeac. Now the time for a final confrontation has arrived. Doctor Illuminatus is a compelling, action-packed story with a real sense of dark magic threaded throughout the exciting plot. De Loudeac is a wonderfully frightening over-the-top villain straight out of a nightmare. Be warned. Scary stories don't come much better than this. Doctor Illuminatus By Martin Booth Published by Puffin Books ISBN 0 141 1310375 John Millen can be contacted on MillenBookshelf@aol.com .