Frederik Barth's pioneering ethnography of the Omani town of Sohar was, along his wife Unni Wikan's book Beyond the Veil one of the first ethnographies of Oman ever published. He and his wife obtained rare (at that time) research permits and undertook several visits to Oman in the mid-1970s, where they based themselves in Sohar, which at that time had no electricity or running water.
Many things have changed since Barth and Wikan's study, not the least of which is that Oman is a much more technologically developed, not to mention open country than it used to be. There are paved roads all the way up into remote parts of the mountains and most places now have electricity and running water. Indeed the achievements of Sultan Qaboos in the last thirty years are quite impressive.
Because of these changes, some of the book's details feels a bit dated. I was also constantly annoyed by how much theory Barth uses to demonstrate a (now) obvious point--the fact of someone identifying as Baluchi or Arab does not explain who they are in some final sense. Barth is obviously keen to engage the larger mid-1970s theoretical debates about the role of culture and its relationship to economy, politics and society.
Nevertheless there are good sections in here on women and men, the role of the khaddam and the pattern of social relations. In particular Barth's description of Soharis' approach to conflict and explosive social situations is very insightful.
Ultimately the book is unsatisfying, despite its useful details, because of an almost complete failure to engage with Islam as a factor of analysis in any meaningful sense. There are discussions of capital and labor, of various ethnic groups and their relation to social status, and a general appreciation of Sohari social life. But Barth doesn't explore the obvious impact of Islam on the behavior and lives of the community, or doesn't seem to consider it relevant enough for any sustained discussion.