It's always great to talk with Dan Saffer. This interview about visual interaction design for his upcoming book, Designing for Interaction was no different.
“Think of visual design as the “voice” of interaction design and information architecture. It communicates the importance of (and relationships between) the content and actions within an application.” - Luke Wroblewski on Visual Interaction Design
For those interested in more, Dan's book is available for pre-order on Amazon now.