Before getting angry, consider the positives as well. There are roughly 3 camps of people reading your book online: (1) This group will use your book as a fre

Before getting angry, consider the positives as well. There are roughly 3 camps of people reading your book online: (1) This group will use your book as a free reference because it's available but _cannot buy your book_ (think poor student, 15 year old with no credit card and other priorities, third world country - too expensive). You didn't gain a paying reader but they are not hitting your existing stash of cash, just potential earnings. On the plus side, they know of you now because of your book. Maybe you can actually get paid for a speaking gig. (2) This group will peruse your book online a few times but _will buy it_ because they prefer to have a hard copy they can read in their cubicle, on the train, etc. A win for you. (3) This group can afford your book and _would have bought the book but now will not_ since it's available online. A loss for you. However I have a hunch (though no data) that this group is a minority especially when it comes to the well paid (and often reimbursed) group of engineers who are the market for your book.