I can't abide book thievery, but I don't see the fault in buying a copy of a book from a store, then downloading a vritual version of it "just in case". This is not something I'd do, because I don't like virtual books, but I don't see the difference between this and buying a CD, then making a copy of it on my computer in the event that the disc is scratched.
This is not the same as buying a magazine from Wal-Mart, accidently ruining it, and then walking back into the store to swipe another. Cars (to reference David R. George's earlier example) and magazines are physical objects, tangible. If I take another one, I am removing it from the shelf. It is no longer physically possible for someone to buy that car, or that magazine, once I have made off with it. This is not the case with intellectual property. By copying a CD or by obtaining a pdf version of a book for backup or convenience, I am not depriving anyone of additional sales. I am simply preserving or increasing the usability of the property I bought. Take music CDs again: should I buy a CD, and then buy 12 mp3s, just so I can listen to the same music in my CD player and in my mp3 player? Sounds silly -- so I don't.
Of course, I understand that those who write or publish books would rather I buy additional copies for backups, but that's not going to happen. I can't justify paying full price twice for one use. Intellectual property is a squirrelly issue, but our best way to navigate it is to think about the consequences of our choices. Take the pulp fiction case mentioned earlier by Shon T'Hara. The books are out of print, the authors are are dead and have no estates. No one is profiting by those books, and there is no harm in downloading the virtual versions to enjoy. No harm, no foul. Now, if you downloaded the books, printed them, and then sold them -- that's questionable, because you're making money off of someone else's work.
Apologies to the authors who find this stance offensive, but intellectual property isn't bound by material property's rules. I grew up in a world that recognizes that, one that is trying to understand which rules apply and which do not. I've made my own rule (in regards to thinking about the consequences), and am determined to do right by the musicians, authors, and PC gaming firms whose work I enjoy.
And again, it's a moot point in regards to Treklit -- I have no use for electronic books.