Unknown to me and maybe even id Software way back when, 12 years ago a couple Hungarian DOOM novels were written and released (bottom two books). Of course I know all about the English DOOM novels by Daffyd ab Hugh but these are a surprise to me.
Scans of these books are posted in my DOOM photo section.
The top two books comprise Masters of DOOM split up. The translation of the text is "DooM Legendája (Legend of DooM). Hogyan változtatta meg John Carmack és John Romero a világot (How did John Carmack and John Romero change the world)".
Thanks for the info, Timea Cseke (IMPgirl)!