Am I missing something? This just appears to be a link to buy some guy's ebooks.
I also just left without reading it, due to the ads.
I'm actually in the process of overhauling the design of the site, particularly with regards to mobile, as the current Bootstrap-derived design pushes all sidebar content to the top on mobile/table.
That said, I'm not sure of the value of linking to part 3, unless the idea is it is the latest and already links back to parts 1 & 2.
Each part of the series is designed to cover the "typical" modules on a UK four-year undergraduate Masters of Mathematics degree.
However, it can be challenging in the latter two years to include a broad enough set of modules to cover all interests, so I have had to stick to those "core" modules likely to be found in many degrees, as well as those more specifically related to quant finance and machine learning.
However, it is my hope that individuals will be motivated to look at other areas as well, even if they're not directly related to career paths!