patterns & practices Application Architecture Guide - v2.0

A very recommended reading : patterns & practices Application Architecure Guide 2.0 Beta 1

"This is the guide to help solution architects and developers make the most of the Microsoft platform.  It's a distillation of many lessons learned.  It’s principle-based and pattern-oriented to provide a durable, evolvable backdrop for application architecture.  It's a collaborative effort among product team members, field, industry experts, MVPs, and customers.  Keep in mind it’s Beta so there’s still moving parts and we’re processing quite a bit of feedback across the guide."