I have an older edition of this book, and have ordered this edition for a friend. This is an incredible book, you can learn very simple techniques in minutes, that will amaze your friends and family with the speed and ease at which you can do math. You can write the answer down without any calculations as the work is done very simply in your head. This is a book I delve into from time to time, in an effort to really acquaint myself with the techniques. The only prior math’s knowledge you need is the ability to count to 10! Would revolutionise maths if we taught this in schools!