This chapter’s aim was to introduce themes and issues in sensation, perception and attention. In doing so we have discussed how we manage to detect, process and manage information from the noisy, information-rich environment in which we live. We have shown how we construct a representation of the world through a combination of bottom-up and top-down processes, and highlighted the role of experience and context. Our sensory, perceptual and attention systems are powerful tools that work together, but our resources are finite. It feels as though we experience and represent everything. In fact we do not do this. Instead we have evolved systems that extract what is necessary to interact with our world, and at best our representation of the world is adequate, even if it is not accurate. Human perception is not perfect and we do not fully understand it, but it works just fine . . . well, most of the time!