Fantastic book. A parallel history of 20th c. electronic inventions (roughly, from electric light to the transistorized circuit) alongside the graphic art used to communicate the technical functioning and conceptual significance of these inventions. The artwork is drawn mostly from trade periodicals, and Prelinger often highlights the background of the artists, who sometimes went uncredited. The technical writing is fairly advanced for a general-audience book; but often, understanding the precise functioning of an invention is critical to both the next step in the inventions chain and the work the artists had to produce to communicate the invention.