Complex sentence: Lummis also decided to enlarged, revised and republished "Some Strange Corners of Our Country" as "Mesa, Canyon and Pueblo" in 1925, and became engaged once again in a civil rights crusade on behalf of the Pueblo Indians.
Split into simpler sentences: Lummis also decided to enlarge, revise and republish "Some Strange Corners of Our Country" as "Mesa, Canyon and Pueblo" in 1925. He also once again engaged in a civil rights crusade on behalf of the Pueblo Indians.