The body is the most complex machine in the world, but what happens when the parts start to fail? Meet the scientists facing the challenge…

Is the bionic human just around the corner?

'Mary Roach offers a fascinating tour of the wonderful world of regenerative medicine.' TIME, The Most Anticipated Books of Fall 2025

Our bodies regenerate at a remarkable rate – our skin replaces itself every month, our blood every four. You can remove ninety per cent of a liver and it’ll still grow back to its original size (please do not try this at home).

Others – the brain, the heart, the eyes – are more complicated. These stay with us for life. So what do we do when they break down? For centuries, medicine has searched for answers – sculpting noses from brass, borrowing skin from frogs and hearts from pigs and crafting eye parts from jet canopies. And as technology has grown ever more ingenious, so have our solutions.

In Replaceable You, Mary Roach sets sail on the uncharted waters of regenerative medicine, exploring the remarkable advances and difficult questions prompted by the human body’s failings:

• When and how does a person decide they’d be better off with a prosthetic than their existing limb?

• Is there a sensitive way to harvest tissue and bones from the deceased?

• Which animals might be the best organ donors?

Through experiments and interviews with patients, physicians, pathologists, engineers and scientists, Roach immerses readers in the wondrous, improbable and surreal quest to build a new you.

'Addictively readable... Don't miss it.' Deborah Blum, author of The Poisoner’s Handbook