These books come from former library of Auschwitz III Monowitz, where IG Farbenindustrie had a big chemical factory, and where thousands of slave labourers (over 500.000) were used, mainly from & KL Auschwitz . This books comes from that former library, which passed completely to the Dwory Factory, which was the company who run since 1945 a synthetic benzine factory in the same place till the 90s, when it closed down. They are all on chemistry, physics, geology, etc. All science based books. These ones come with many stamps from Auschwitz and IG Farbenindustrie, different stamps, and some crossed out and substituted by others from Dwory, the Polish company. These books are about Chemistry. This is very difficult to find and a real been there item!