Since this is a physical book, you cannot start printing without knowing how many possible people are interested in buying it. So before we talked with relevant printers we started the crowdfunding campaign. From our calculations, to print on high-quality pages and to have a hardcover (which cost way more than a simple regular paper cover) and to cover also the transportation expenses we had to sell over 200 copies.
On the initial launch, we ended up selling 400 books. After we raised the amount, we started to look for printers. Most of the pages, 98%, from this book, have images, which means each page cannot be printed as a regular textbook, but more as a photo album, so the pricing is pretty different from a simple plain textbook.