Perry Cook’s principles of NIME and revisions:

Principles for Designing Computer Music Controllers (CHI-2001)
+
Re-Designing Principles for Computer Music Controllers (NIME 2009)

organic user interfaces (pls see the articles linked on the sidebar)
http://www.organicui.org/ 

Hiroshi Ishii:
Tangible Bits: Towards Seamless Interfaces
between People, Bits and Atoms
+
Radical Atoms: Beyond Tangible Bits