This book is awesome. The authors give an overview of books from all epochs of literature starting with Dante's Divine Comedy. This has been done many times before and so actually is nothing special. What makes the book so special is the way the books are presented.
The authors use are very modern language and try to explain the contents of the books in a very simple way. Their explanations are often quite funny, e.g. when talking about Faust they say "Faust is suffering from burn-out". Often there are also drawings illustrating the storylines. For example there is a one-page comic-like drawing showing what happens in Anna Karenina.
There are also factsheets on different topics, e.g. nom de plumes, literary prizes, first sentences (I loved the comment to the first sentence of Finnegans Wake: "At least you know at once what to expect").
The book is a very enjoyable read. I'm only not so sure whom it is actually written for: the authors say that Literatur! can be used as a manner to introduce non-readers to literature. But I don't believe a non-reader will read this book. On the other hand it is not serious enough to be a good guide to literature for someone who is reading a lot. I really enjoyed it because I have read many of the books mentioned and often got a new perspective on them.
Another minor negative point is that for the last 20 years there are hardly any books. This is a bit weird compared to the rest of the book when titles I haven't even heard of are talked about in detail. But as the book is really great this didn't bother me too much.