When reading about the Holocaust, I tend to wonder less about the experiences of the Jews & the many other victims of the racial "purge". (The Romani people, homosexuals, the mentally & physically handicapped) and more about the German citizens.
How could ordinary people have participated in this?
If any book is going to give us an answer, it's this one. Historians study it in the ongoing debates about how the Holocaust played out.
Mein Kampf ("My Struggle"), being the memoirs/political ideology of a megalomaniac, it embellishes, misrepresents and omits whatever might belie the desired impression.
It is important not for what is says about Adolf Hitler, but for what he wanted the world to believe about him- and what people wanted to believe about him. In this book, we see that Hitler presents himself as a patriotic, heroic, god-fearing defender of German values.
This book epitomizes evil for many people (see list of restrictions and bans here). But books in themselves are never evil- it's the ideas people have a problem with--in some cases, this is understandable. But how do you fight an evil you don't understand? How do we unravel the dark knot that is human evil if we can't even stop and examine our opponent?