Can you remember the first time you encountered true darkness? The kind that remains as black and inky whether your eyes are open or closed? Where you can't see your hand in front of your face? Jacqueline Yallop can. It was in an unfamiliar bedroom while holidaying in Yorkshire as a child, and ever since then she has been fascinated by the dark, by our efforts to capture or avoid it, by the meanings we give to it and the way our brains process it. Taking a journey into the dark secrets of place, body and mind, she documents a series of night-time walks, exploring both the physical...