Hi

I just browsed the new book of rebecca wirfs-brock: Object Design: 
Roles,....
and it looks really interesting.

Stef

Dr. Stéphane DUCASSE (ducasse at iam.unibe.ch) 
http://www.iam.unibe.ch/~ducasse/
  "if you knew today was your last day on earth, what would you do
  different? ... especially if, by doing something different, today
  might not be your last day on earth" Calvin&Hobbes