James F. Fisher sums up his anthropological experience with the Sherpas in Sherpas: Reflections on Change in Himalayan Nepal. Fisher has the unique experience of helping to create the single biggest vehicle for cultural change in a community (the Lukla airstrip) and then becoming an anthropologist and studying what happens. The book begins with a narrative (including journal entries) of his first trip to Khumbu, as an US Peace Corps volunteer and aide to Sir Edmund Hillary during the 1964 expedition / project that constructed the airstrip, as well as three schools. After studying anthropology, he decides to return to Khumbu to see what effect the schools are having upon the culture of the Sherpas, but soon learns that the airstrip (that was originally designed to fly in supplies to build a hospital) has outgrown its original purpose and had the greater effect than the schools. Whereas Khumbu had 50 international visitors in 1964, thousands of tourists were visiting Khumbu annually in the 1970s, when he returned. (Instead of a 9-14 day walk, it is now just a 40-minute plane ride away.) The book includes results of his education studies as well as subsequent studies made during the 1980s, focusing on education and cultural change. Overall, the book is not as rigorous as an Ornter (Life and Death on Mt. Everest) or as intellectual as an Adams (Tigers of the Snow and Other Virtual Sherpas), but Fisher's practical topics and easily-understood language make this book approachable to general audiences, and his intelligent conclusions make it worth a read. I can understand why Ortner seemed pleased to cite him!
Fisher generally brings up Everest regarding a specific Sherpa's work history. There are some other references as well, however. He discusses the high percentages of Khumbu Sherpas in the early climbs of Everest, especially in the 1960s and 1970s. As Khumbu Sherpas have been able to find safer profitable work, their numbers have dropped over time, so that now (1990, in his book) higher percentages of Solu Sherpas are participating on mountaineering expeditions, and other ethnic groups (Tamang, Newar) are beginning to get into the business. (Today (2012) the trend continues, so that an average Everest "Sherpa" staff regularly contains a variety of ethnic groups.) He also brings up the 1988 Nepal-China-Japan Friendship Expedition in the context of measuring the change in Sherpa cultural identity, as the Sherpa climbers wore Nepali formal dress to a reception in Kathmandu, when before, during similar receptions, Sherpa climbers had worn Sherpa formal attire.