Boken Det var en gång en sjö skildrar en buddistisk tankevärld i berättelsens form. Så här skriver Dalai Lama i bokens introduktion: "This book by Elisabet H[ä]renstam is about Pema Dorjee's childhood in Tibet. It is a story about the memories of a Tibetan when nature was not destroyed, animals were not afraid, lakes were clean and mountains were majestic. These memories have been beautifully illustrated by Tashi Topden, a Tibetan artist who is well aware about the land and nature of Tibet as it existed before China's occupation. I am confident that this book will help readers, especially the children, to learn something about the past, peaceful environment of Tibet."