Andy Burns wrote:

Welcome to the brave new world of Digital Rights Management :-(

Some new meaning of the word "welcome" of which [etc.] ...

Seriously though, what are they trying to protect? All serious users
are going to have to buy the final printed copy in any case. Changes
between this and the final version are inevitable, and (AIUI) this DPC
version does not contain the definitions section, nor an index.

--
Andy