Using a handmade pinhole camera, Nick Livesey, who has ridden with The Fireflies since 2001, has documented mountaintop scenes from The Fireflies' rides across the Alps.
Weather-beaten, high open spaces are juxtaposed with the clinical lifesaving machinary obtained as a result.
To date, The Fireflies have raised more than £750,000 in support of the charity.
People who have become a Firefly, as well as those who have contributed their support to the ride, will be able to see exactly where the funds have been going.
The Hammersmith Hospital houses the Leuka charity, which will benefit from £40,000 worth of funding if all 1,000 editions of the book are sold.
Please support The Fireflies and Leuka by purchasing your copy of Mountain / Machine.
For more information and details of where to purchase a copy, go to www.nicklivesey.com/thebook or contact Nick Livesey on email@example.com.
The London exhibition of the portraits opens at The Engine Group's 5th floor Gallery on Great Portland Street on Thursday 4 June.