A tour de force of imagination and exposition, he takes us by the hand and guides us through uncompromisingly challenging territory that expands our minds and encourages a playful and exploratory approach to study. The puzzles, he says, are like toys. We should pick up the one we most enjoy, and play with it. Whether you are an aspiring scientist or an old-hand, pitting yourself against these problems will test your ability to think, and inspire you with curiosity and enthusiasm for physics. Presented with charm and wit, the questions span the gap between high-school and university-entrance standard material. Detailed answers are lightened with a fascinating and refreshing blend of scientific history, application and personal anecdote.