Just for personal use as all the books were still in copyright and I own the paper versions, it was a (probably legal) fair use of them purely for reference while studying.
I often needed to find information in the books and couldn't reasonably carry them all with me every day between work and uni.
I'm a heavy believer in more rights when you buy a digital asset, but I don't think it's reasonable that buying something in one medium should give you automatic freebies in another medium. That other medium still needs to be produced, at a cost to the publisher. Does buying the book give you the rights to the audiobook as well?
That said, there should certainly be no restrictions to creating your own versions of things you own in other media.
Print houses are increasingly using the same source and layout files for printed books as they are for ebooks. This means that there is little to no difference or extra cost to produce the alternate media version here.
I totally agree that an audio book has an entirely different production path and it's own entirely different staff and company that needs to make it's own costs back. But that argument is becoming less and less relevant for physical vs digital books.
Many non-traditional/smaller publishers and printers, such as No Starch Press, offer free copies of the ebook version when you purchase the physical copy and offer the digital copy at a reduce price compared to print.
I've not explained well, I don't expect the producer to have an obligation to create a copy, just to exhaust their right to sue you for having a copy. But, if the same work _is_ available in another format then I think it would be reasonable to expect the seller to provide it (it costs them bandwidth, nothing else over what they're already spending).
Audiobooks I'd say are new works. If you buy it on a medium you should be allowed to rip it and vice-versa, however (currently not allowed in UK).
> But, if the same work _is_ available in another format then I think it would be reasonable to expect the seller to provide it (it costs them bandwidth, nothing else over what they're already spending).
Sure, but it's worth something to you.
I just downloaded a productivity app. The free version is great, so I don't think I need to upgrade, but I noticed that the paid version includes a Pomodoro timer. Would it cost anything for the company to turn on that feature for me? No, of course not. It's clearly just an attempted to make more money. But an attempt to make more money is exactly what they have a right to do. That's why they're in the business.
I see where you're coming from, but format-shifting is different, a different class of product to a locked extension of digital good.
The only inhibition to me making or acquiring a copy of a book in my preferred format is copyright law, I already have a copy on paper; I can download or make a copy easily. That should be allowed as I have paid for a licence to the work (and I think is allowed under Fair Use in USA). As the copyright holder already has a digital copy the restriction of it is silly -- for the demos, who supposedly give the rights in copyright, the benefit lies in making that copy of the work available rather than forcing the extra work of having someone scan it and upload it and make it available. This later route also enables copyright infringement far more readily than the former does.
I often needed to find information in the books and couldn't reasonably carry them all with me every day between work and uni.