How do you define photography in a single sentence? No-one can agree –so this new book charts 200 years of it instead

A candid, colorful 1960s photograph capturing a group of adults and a young boy laughing together while sitting with their legs dangling over a concrete sea wall at a public bathing area.

Ask a room full of photographers to define photography and you'll get a room full of arguments.

Indeed, as This is Photography: The First 200 Years recounts, in 2010 the artist Mishka Henner compiled 3,000 different sentences attempting to pin down what the medium actually is, pulled from critics, philosophers and photographers who'd each convinced themselves they'd cracked it.