My workday is over. What do I want to do now? I picture calling my wife to suggest dinner at that nice Italian restaurant and imagine the taste of gnocchi quattro formaggi. Then I remember promising to look after the grandchildren that evening. My colleague at the desk next to me has no idea of this rich world unfolding in my head. This is the world that I call my consciousness, my mental state, my mind, or my thoughts. It is comfortably private, and I cannot imagine having an intelligent life without it. My behavior and pronouncements are but the tip of the iceberg that is my consciousness. Is this consciousness something that can be replicated? In our quest to build smarter computers and robots, will we one day develop machines that have an internal mental life comparable to our own?