The content will offer you in 222 pages a list of more than 4200 different groups and + 9200 references (Vinyls, CD, K7, Demo K7, Digital) in the styles: HARD ROCK / HEAVY METAL / PROGRESSIVE METAL / SYMPHONIC METAL / STONER / FOLK METAL / THRASH / DEATH THRASH (period 80's until 1993) and DOOM. (So NO Death, Grind, Hardcore, Black Metal or other funeral Doom or any other violent or overly delirious style).
There will also be statistics (number of groups by department and number of groups of a style by department for example).
Some pages will explain you well on how to understand and decipher my definitions of styles, some explanation on the supports described...
Know that there will be no photos or covers because otherwise it would have taken 500 pages... It's a choice.