Another formative influence. I learnt about the elements and principles of design whilst studying, but it took several years for me to track down the source. The quantity of exercises and interdisciplinary nature of this book make it a must-read for me.
This was the book that made me see that perhaps I could be a designer after all. The focus on product design, engineering and empathy was refreshing because of the focus on people, and designing products and systems that work for the people using them, not the other way around.