Some books on Amazon are DRM free. The publisher is the one who decides if they want to use it.
Until they offer a cast-iron, legally-binding guarantee that any ebook I buy from them cannot be taken away from me, they don't get my money.
If I buy a book, it's my book: If the bookshop I bought it from takes it back, then that's theft.
As far as I'm concerned, the same holds true for ebooks. I buy it, it's mine. Period. Until Amazon agrees with me, I don't buy their ebooks. It's that simple.
Also, isn't stripping DRM from Amazon ebooks against the TOS? Potentially exposing him/her to some legal trouble?
Link: http://shop.oreilly.com/category/customer-service/dropbox.do
As others have said, breaking the DRM for personal uses (backups, changing devices) should be perfectly legal in the US and probably most of Europe as well.
http://www.amazon.com/Neuroscience-Exploring-the-Brain-ebook...
"Simultaneous Device Usage: Up to 4 simultaneous devices, per publisher limits"
means that it has DRM.