Typographia, or the Printer's Instructor.

In 1817, Johnson moved to London, where he set up shop on his own and began work on his nearly 1300-page history and manual of printing, Typographia. The first volume is mainly historical, while the second is devoted to practical information for the practicing printer, along the lines of Moxon and Fertel.

Typographia is notable not only for its length, but also for the care devoted to its composition in an extremely small type. In the larger edition each page is surrounded by an elaborate border made of hundreds of metal type ornaments, while a simple two-line border is used for the smaller issues.