Gravity has an irresistible grip on our curiosity and is able to drive our imagination to completely different theoretical spaces. This very fact alone sets gravity aside from all other types of physical interactions we know. Indeed, gravity is the only physical interaction of which we have a conscious experience and this awareness is with us every second of our life. In this book we set out to try to address the question: '…what is gravity and how does gravity actually work?'. This book is meant as a guide in a journey that will take us from our basic understanding of gravity, the one that is deeply coded in our brains even at an instinctive level, to the more physically detailed and yet incorrect description provided by Newton’s theory of gravity. The journey will then lead us to the mathematically beautiful and physically profound description that Einstein has proposed with his 'general theory of relativity', and that is elegantly embodied in his field equations.