The Golem and The Golem at large are two excellent little books about how science and technology actually works. History of science, so heavy on examples (as the historical subjects tend to be) and light on theory. Several examples of what today would be pseudo science but was treated seriously at its time, because they didn't know what we consider basic knowledge (and you can't get it from first principle...)
Good for anyone interested in science or technology, but perhaps particularly useful for the cultists (if they can be persuaded).