Why can't I make a copy of a Movie DVD?

Most DVDs have two issues preventing you from making a copy of a DVD:
1) DVDs are encrypted with a measure called CSS, Content Scrambling System. CSS prevents people from copying movie files to their computers and from burning these files to a DVD.

2) Movie DVDs are 8.5GB in size called Dual Layer DVDs. Blank DVDs are typically 4.7GB. Blank Dual Layer DVDs are available but not cheap.

Newer DVDs also have other preventive measures such as Arcoos protection.

There are software available to get around these measures but most are not free or legal in the United States:
AnyDVD – http://www.slysoft.com/en/anydvd.html
DVDShrink – http://www.dvdshrink.org/
DVDFab Decrypter – http://www.dvdidle.com/free.htm