The more I read it, the more I like it.
You used the same guidelines I have in my project and if someone is going to do something like that, he'll see that is the best way possible for the reasons you wrote.
There is a crucial guideline I used in my work and I'd like to know how did you deal with that: I'm talking about sources.
I have 2 different, parallel projects:
1. an Access file where I have listed all the makers plus all the models and 2. a collection of folders with all the pictures, webpages, docs I find online.
The 1st is the official one, the one I compile using only (mostly) reliable sources: magazines, books, encyclopedias and similar.
The 2nd is the 'extension' of the 1st...a tool to keep it updated with the latest releases and to keep note of the obscure cars featured only online, for example, at Autopuzzles.
I use the material from the 2nd project also to buy books and look for sources: I bought a book about New Zealand racing cars because some of them were featured here on AP but in none of my books...now I can move them from my project #2 to my project #1.
Back to your book, now.
I saw all your 1st volume, page by page on your facebook page and for example, you listed there 5 selfbuilt russian cars, Aelita, Agidel, Alezonik, Almaz & Altaj.
None of them is in my 1st list because they are not featured in any book, etc.
All of them are in my 2nd work because they can be found in Arunas excellent website....but there are more of them in other sites too..and they are not in your book.
Obviously you can't have them all (I'm trying too but adding Arunas's 355 to the nearly 200 I found in other 2 sites I have the strong feeling I'm still far from that!) but how can you decide what's in and what's out?
You listed racing cars too and that's a landslide of makers: I started to buy books about the rarest ones but for each 1 I add in my list, there are 10 left in my database!
There are excellent websites about race cars, for example the well known one about the Formula 3 cars, but Adams, Aikens and Alfa-Dana are not in your book.
Of course I'm not asking you to reveal your sources but I'd like to know how you decide what's there and what is not.
I'm sure it will be written on your book, but according to what I saw of your 1st book my guess is that you used books but also websites.
I can't figure out how you decide what is reliable for your book (AllCarIndex, for example) and what it's not (or what you simply decided to ignore).
...and now you can see why I'm so interested in your work:
try to imagine how many makers I can move from my p.#2 to my beloved index #1 using your books as a reference!