This history is a very detailed and focused one and I really love the way most information is documented with links. It is a very useful source of primary and secondary documents. It is centred on PGP as a multiform software and tracks all its versions, the people behind them, and the place where they are published. In this sense, it is very complete, but I lack a broaden contextualization. Who are the people that made this history? Why and how did they act as they did? While a recent history of this kind was much more critical and one-sided, this one seems very neutral and objective (in the sense 'based on objects and facts'). But the history is not as flat as this. What about the competition between versions, the tensions between programmers?
N.B. I'm aware that the author's goal was very different from mine. The criticisms I will mention are more addressed to myself than to his work.
This history is an interesting one as it starts with the invention of SMTP in 1981, 10 years before PGP invention, and situates its invention with a 1991 senate Bill 266 to ease electronic surveillance. Major historical events (the release of differente versions of the program, the publication of atlernative competitor (such as S/MIME or OTR), as well as vulnerabilities (e.g. Efail) are mentioned. There are also many criticisms that are mentioned and dated back in time.
However, several elements are missing in my opinion: