'An Essay Concerning Human Understanding' is philosopher John Locke's pioneering examination of the origins of human knowledge and understanding. First published in 1690, it set the agenda for modern philosophy and influenced psychology and political theory. 'An Essay Concerning Human Understanding. Volume One,' covers Locke's attempts to discover where our ideas come from, what it means to have an idea and what an idea actually is. He also discusses theories on free will and personal identity, outlining the notion of the blank slate at birth or tabula rasa, which is then filled in by experience of the world. Regarded as Locke's most powerful and important philosophical work, 'An Essay on Human Understanding' still resonates today.