Finding book-length ethnographies can be challenging because they don't always include the word "ethnography" in the title or description, and there isn't a single word, phrase, or subject applied by libraries to make locating them simple. Here are some strategies you can use when searching for an ethnography in the Wheaton College library book search.
Search for "ethnography" and the culture you are interested in, as keywords:
kw: (ethnograph* OR ethnolog*) pueblo
Search for the subject heading "social life and customs" and the culture you are interested in, either as subject heading or keyword.
su: "social life and customs" navajo
su: "social life and customs" kw: igbo
Search for the subject heading "social conditions" and the culture you are interested in, either as subject heading or keyword.
su: "social conditions" maori
su: "social conditions" kw: tutsi
Add specific characteristics to any of the strategies noted above, usually as keyword, but sometimes subject will work.
su: "social life and customs" navajo kw: family
su: "social life and customs" kw: igbo religio*
Or add specific date ranges (Note: these are publication dates of the books, not when a culture was necessarily studied).
su: "social conditions" maori yr: 1860..1950
su: "social life and customs" navajo kw: family yr: 1951..2013