Hi All - I bought a copy of this book a few years ago and thought I would comment as I can highly recommend it.
The book tracks the progress from the very earliest Siebe Gorman Hardhat Diving in the early 1930's to the most recent pushes (now back in 2005) using mixed gasses and sidemount rebreathers at depths greater than 90m (underwater).
The history of it's exploration and techniques used are well documented and each page carries a number of superb photographs or working surveys - a real treasure trove. Having been very fortunate to dive here back in 2015...all I can say is that having read the book beforehand really added to the experience as you pass through the many areas with historic significance. The huge amount of work that went into this book is apparent on every page and although many people contributed Jim Hanwell, Duncan Price and Richard Witcombe are to be congratulated for the quality of the work. It's something I have gone back to time and time again.
Even if you don't dive it is still a superb read and the fact that if bought in the UK the offer price of £16 (which includes P&P) represents excellent value for money.
You can buy the book direct from the CDG's website here: https://cavedivinggroup.org.uk/product/wookey-hole-75-years-of-exploration/