This book is mostly for people who would like to try Vim out but also can't afford wasting time and need to be productive from day one.
This book is explicitly focused on building an IDE-like environment on top of the Vim. That means configuring and adding essential plugins from the start. Vim theory is also covered to a great extent, but it is rather secondary to the main plot and it unravels as we go towards our eventual goal.
We are using the regular Vim (8+). But all the knowledge can be applied to any other flavor (like Neovim).