When I meet someone, I know them to be a person. I can start to get to know them, learn their history, their views, their aspirations. I may immediately sense whether or not they are a potential friend, someone I shall like and find interesting. I am encountering more than just another body, and I know that they are similarly encountering "me". But what is it that makes me "me"? Is it possible for someone else to know me completely, or is there always going to be a "real me" accessible only to myself? How did I become who I am? Can I opt to change in a fundamental way, or am I stuck with what my childhood made me? And can I every fully know "you"? These questions are absolutely central to our lives. Nothing is more obvious and immediate to each of us than the fact that we exist. But if I ask myself what it is to be "me", the answer is less obvious, so much so that the nature of the self has always been a puzzle for philosophers. There was a time when a majority of people would probably have agreed with Descartes' famous dictum "I think, therefore I am" and considered themselves to be essentially thinking beings trapped within a physical body - the inner voice of thought, the window between the eyes through which we seem to look out onto the external world, the sense of continuity through all the physical changes of life, all combined to make dualism of mind and body seem reasonable. And religion backs that view, encouraging us to see the self as able to survive the death of the body. We are neither machines nor animals, but individuals with significance beyond our imprint in this physical world. But with the development of neuroscience, we have become wary of the dualistic view. Clearly, what I experience as thought corresponds to the firing of neurons in my brain. I am my body, animated but physical. There is no "real" me existing external to my body; my life is defined by chemicals and electrical impulses, and one day - hooked up to a suitably powerful computer - it may be possible for me to become downloadable and reproducible. Science seems to offer an explanation for "me" that requires nothing beyond an analysis of the workings of a brain hooked up to a body. In this materialist view, I am part of this physical world, nothing more; and the wonder of the human being - for a sense of wonder remains, even in a materialist analysis - is that it is so complex, so able to relate and respond to the rest of the world. But, for most people, the question of the self is actually about what it means to be "me", and to that question, neuroscience gives no answer. How is it that the tiny baby takes on a personality, grows to have views and attitudes, experiences preferences and becomes a unique person? What is the mechanism that enables us to become what we experience as "me"? I suggest that the answer lies, very straightforwardly, in the interaction between experience and memory. The first thing we need to recognise is that the mind is not some passive container of offered experience; it goes hunting. Immediately after birth, the baby starts rooting around to find a breast, puckering up its lips ready to suck and find satisfaction. From that first moment, it starts a process of engagement with its world. It soon knows when it is cradled up against a living body, and when it is put down in its cot. It starts to map out its world, not just in a physical sense, but in terms of comfort - a map that shows where it wants to be. And this process of active mapping, I believe, is the mechanism by which personality continues to be formed. As we look out onto our world and engage with it, we encounter things that are important for us - they find their place on our "map", and when we come across them again, we anticipate what they will be like for us. Years pass and the simple contours of our basic map become overlaid with new experiences, new values. As we open our eyes on the world every day, we impose upon it the imprint of every experience we have ever had. We do not see the world as a stranger might; we see it through our superimposed mental map. It is thus memory that creates character, and were I to lose my memory I would no longer have a sense of being "me". That, of course, is not to imply that there is some map located somewhere within the brain, but that the processing of experience adds the quality of "me" to raw data coming from the senses. We are not so much a thing as a process, mapping ourselves in our world from cradle to grave. We can, of course, pretend to be many other things. We can re-create ourselves on Facebook, or present ourselves to the world via a website, seeking to define ourselves as we would wish to be seen. Yet the temptation here is to opt for some limited view of who we are, leaving aside the more complex patters that actually shape our lives. Join a dating agency and you will have to give some potted account of yourself, but you know it will never be the whole truth. We all engage in selective PR! We also need to recognise that the "me" I want to present to the world is something of an illusion, albeit a necessary one for practical purposes. We are never fixed; we are a process, not a thing. I am not located in my brain, but am the product of what happens when this body interacts with its world and remembers what it finds. I am the map that is constructed; I am the particular quality that gives my experience its uniqueness. And the implication of all this? Here is the final paragraph of Me: "There is no mystery to consciousness; no secret, hidden "me" waiting to be discovered; no ghost in the machine. A human person - described as "me", experienced as "I"- is simply the most wonderful product of an evolutionary process that allows senses and brain to work together. And the most amazing thing is that it not only gives character to characterless neurons and sense organs, but it also transforms the external world of physical matter into one that is mapped out with value, beauty, friendship, meaning and significance."