ISSUU is a site where you can access a huge number of books and magazines. The problem is that many of them have been uploaded without the authorization of the author or publisher.
What do the people posting your book get out of it? They can add links to their own sites, charge a reading fee, or place ads. Or they may just want to share.
For instance, thanks to a reader of this blog, I learned that someone named Andrew Yi from Taiwan uploaded my book, Your Writing Coach, without permission from me or the publisher. I've now lodged a complaint but the first edition of the book has been up a long time and gotten 112 "likes" which suggests at least that number of people have accessed it on ISSUU.
I wonder whether ISSUU is at all concerned with who downloads what. Yes, you can upload your own book, but does ISSUU really think that McGraw Hill gave permission to Kamal Al-Dallam to upload "Business Writing and Communication"?
There are hundreds, probably thousands, of examples like this.
If you or someone you know has a book out, check ISSUU to make sure it's not being pirated there.