Can you ... Forget this line? Dig half a hole? This book asks you to imagine and think about some things. That sounds easy, right? Anyone can think stuff. You don't even need to be standing up. We shall see. Good luck. Metacognition is the act of thinking about thinking and forms the basis of all critical thought. It is also a concept that comes easily to children whose inquisitive nature makes them a natural at engaging in abstract questions and open-ended thinking. The Very Hard Book starts that 'thinking' journey and has a great deal of fun in the process.