Tschaturanga, Edition Olms, 40 volumes

In Ricardo (a kind of Swiss eBay) I am selling 40 volumes of Tschaturanga, Darstellungen und Quellen zur Geschichte des Schachspiels. Edition Olms, Zürich. Interesting if you are living in Switzerland, South Germany or Austria.

https://www.ricardo.ch/de/a/schachbuecher-konvolut-tschaturanga-olms-40-baende!-1221361018/

So I looked online and I see several volumes of the series priced at $40 per volume.

Can you tell us more about this very expensive series?

There are different prices depending if the books have hardcover or not and how rare the books are. Some of the volumes are not available. 
However, after your post and after checking the prices again I decided to give a much lower starting price (20 Sfr per volume).

I got these books from a woman after her husband passed away.  She gave me also some chess sets, other books and chess boards. 

From the German Wikipedia:

Tschaturanga is a series of publications published by Edition Olms, Zurich, since 1978. It contains reprints of important works of chess literature. It is named after Chaturanga, who is considered the forerunner of chess. Collaborators in this series were Viktor Kortschnoi, Klaus Lindörfer and above all Christiaan M. Bijl, who wrote a blurb and/or a foreword for most parts.

Yes, I got them like this.

I sold the whole series for 270 Swiss francs. An incredible low price. However, I have more space at home. And I got the books for free, so I am happy. 

Somebody got a great deal, hopefully they found a good home.

Yes. I have the impression that someone bought them to resell. It’s okay like this. I still have a lot of books to sell in the next weeks.