I measure a design book's impact on me by the amount of sticky notes I leave in the pages. When I was done with Simple & Usable (web, mobile and interaction design) by Giles Colborne the volume was strewn with marked out passages to refer to. Following the book's guiding principle, it's a simple and straightforward walk through methods to adopt when designing interactions. Methods which help to strip away superfluous elements, creating a more successful design.
Simplicity is about control.
Unraveling your users' emotional needs can be tricky, and made worse by the fact that many people are uncomfortable sitting in a design meeting talking about feelings.Fortunately, when it comes to designing for simplicity, the key emotional need is for users to feel that they're in control. Firstly they want to feel in control of the technology they're using. Secondly, they want to feel in control of their lives.
I recommend it to anyone who has Design, IA or UX work and wants to create better products, services or brands.