This is a complete set of the Smithsonian Jornal of History which ran for three years.  It was produced quarterly between 1966-1968 with a total of 12 issues, each with their own table of contents.   The contents cover a large range of topics (see images), primarily covering areas of US history that were part of the Smithsonian's interests.  After the main articles in each issue, a Notes and Queries section followed.  As befits Smithsonian publications, the illustrations are excellent. Some have limited color, but most are monochrome/black and white.