Who wrote about a prosperous utopia in the mountains of Tibet?

The concept of a prosperous utopia in the mountains of Tibet is notably explored by James Hilton in his 1933 novel "Lost Horizon." In the book, he introduces the fictional paradise of Shangri-La, a hidden valley where the inhabitants live in peace and harmony, untouched by the outside world. This portrayal has since influenced popular perceptions of Tibet as a mystical and idyllic place.