2 books about BIOS

Recently, in one TOI related to BIOS, one experienced BIOS engineer recommendsBeyond BIOS to us, who don't write BIOS code, but need to know something about it. It proves that there are still books about BIOS, so I do some search through Google and find another one: BIOS Disassembly Ninjutsu Uncovered, which also dive into this topic deeply.
The 2 books are both out of sale from Amazon, especially the latter is in unreasonably high price from some sellers, but one good news is that it is freed by its author for free download here.