Ageless: The New Science of Getting Older - Kindle Edition - £2.29 @ Amazon

This book gives a summary of research into the ageing process.
Andrew Steele is on a mission to get ageing treated as a disease that might be cured.
Not read the book yet but watched a few videos he's done and I think they're worth a watch.
Here's one he gave at The Royal Institution

It's reduced on the Play store from £7 to £5 but even cheaper on Kindle

Full title is
Ageless: The New Science of Getting Older Without Getting Old