Catich's "third book"?

In the introduction to The Origin of the Serif, Edward Catich writes: "The third book of this series, if the author is granted time to complete it, is to be entitled "The Imperial Alphabet" and will consist in a thorough study of each of the Trajan letters not only from its visible, external shape but also from its equally important internal kinesthetic causes. From the knowledge of the internal factors it constructs those letters, H, J, K, U, W, Y, Z, and &, which complete the alphabet but were not used in the Trajan Inscription. Since the Romans did not use the Arabic numerals familiar to us, the same method is used to shape numerals having an alphabetic kinship to the Trajan letters. To do this the author has tried to put himself into the position of the sign-writer who wrote the Trajan Inscription had that Roman been asked to write these missing letters and numerals."

Am I correct in surmising that this book never happened? Did this project see light of day in any other form?