Gently’s Return of*
Review of the Constable Kindle eBook edition (2011) of the Cassell hardcover original (1961).

I had some fun searching for illustrations related to Gently to the Summit and that reflects in my rating. The case itself involves the return after 22 years of an apparent 'lost presumed dead' climber from a Mount Everest expedition in the late 1930's. The returnee makes himself known to his club and is met with doubt. Then another member dies under suspicious circumstances at Mount Snowdon in Wales and the returnee is the main suspect. Snowdon is a regular site of training runs for Mount Everest, although you can also walk up to the summit by hiking trails or travel by railway.

Chief Inspector Gently is called in from Scotland Yard's CID Central Office and has to solve the question of both the new death and the original disappearance and reappearance. He ends up reconstructing the crime by arranging for all of the suspects to walk up Mount Snowdon yet again.

See photograph at https://sp-images.summitpost.org/294136.JPG?auto=format&fit=max&ixlib=ph...
A photograph of the original Snowdon Café at the summit of Mount Snowdon in Wales in the 1930s, which is the site of various murderous happenings in ‘Gently to the Summit’. The original café was once described by Prince Charles (now King Charles III) as the ‘highest slum in Wales’. The original building was demolished in 2006 to make way for a modern visitor’s centre and restaurant. Image sourced from the Summit Post.

See photograph at https://i.guim.co.uk/img/static/sys-images/Arts/Arts_/Pictures/2009/8/3/12492868...
A view of the modern Mount Snowdon visitor's centre which opened in 2009. Image sourced from an article High Tea, Mount Snowdon's Magical Mountaintop Cafe in The Guardian, August 2, 2009.

See dust cover at https://images-na.ssl-images-amazon.com/images/S/compressed.photo.goodreads.com/...
The dust cover of the original hardcover published by Cassell in 1961. Image sourced from Goodreads.

Footnote
* I was going to title this 'Gently's Return of Martin Guerre', but then wondered how well the classic 16th century historical case of imposture is known. You can read about it at Wikipedia. Note: The historical case is not a spoiler for the Hunter book as the fates are completely different.

Trivia and Links
The George Gently books were adapted as the TV series Inspector George Gently (2008-2017) with actor Martin Shaw in the title role. Very few of the TV episodes are based on the original books though and the characters are quite different. The timeline for the TV series takes place in the 1960s only. A trailer for the first episode can be seen here. ( )