[beej71]

If you don't have the money, you don't have the money. IMHO I'd rather have people without the means pirate books rather than go without. (Though the library is usually an option.)

But if you do have the means, drop the author some bucks for their work. And I can assure you, it's a lot of work. My tip jar doesn't get a lot of action, but when it does, I'm very appreciative. Here's someone who appreciated the work enough to drop me a few dollars for my labors when they didn't even have to.

[aeblyve]

I've read some of your stuff over the years and was appreciative of its accessibility.

https://pages.cs.wisc.edu/~remzi/OSTEP/

The above is another example I appreciate: the authors charge for physical copies and complete documents but generally make the work content available for free. I've bought a physical copy in that case because I really valued the work.