The purgatory of Metal to discover urgently!

Great idea that this book which again, is fairly well done and clear.
This Volume 1 covers 20 years (70 and 80) and contains about 160 chronic albums, I guess Volume 2 deals 20 years after (ie 90 and 00) to match the title.
The idea is very good indeed for the author offers a selection of albums, in three relatively unpublished criteria.
1 - estimated subgroups albums.
2 - groups of albums to discover unknown.
3 - lesser known groups known albums.
The selection is relatively new and really brings a plus for fans of the genre.