A very interesting book (at least for me, for obvious reasons), but unfortunately available only in Polish. Still, most of it is pics, so it still has some merit even without knowing the language
"Polskie samochody wyścigowe" ("Polish Racing Cars") by Robert Steć, published in 2011, edition limited to 1000 pcs, 240 pages, 370 photos, 87 PLN (21 EUR, 27 USD).
This book chronicles the post-war racing cars made in Poland until early 1990s (which makes it essentially all such cars, as I don't know about any pre-war polish racing constructions, nor were there really any built in the recent years, apart from a few one-offs). It mostly focuses on the Rak/Krab/Promot cars, but devotes some place to self-made cars too.
Table of content:
1. Racing one-offs
2. Rak and Krab
3. Rak Formula Junior
4. Rak Formula 3
5. Promot: Formula Polonia & Easter
6. Other constructions
7. Where are they now?
As I said, only in Polish, so probably won't be of much interest for any of you, but it's a book worth mentioning, especially that even in Poland most of the people don't know a thing about these cars, usually aren't even aware that there were racing cars produced in Poland.