This book started there, and took me far beyond anything I'd ever learned in an NLP seminar. It's a great book. Due to my being out of town, there was no June selection. Solving by Joseph O'Connor , Ian McDermott , 1998. NLP's early development was heavily influenced by Gregory Bateson and systems thinking.
Systems thinking is somewhat the opposite of traditional Western scientific thinking.
While the scientific method is about isolating parts of a system and understanding the pieces, systems thinking is about understanding the relationships within a system, and how all the parts affect the others. For example, a thermostat and heater must be analyzed as a system. I was so intrigued by systems thinking that I went down the road to MIT and audited the System Dynamics class, an extremely rigorous version of systems thinking. It was an amazing experience. In this book, Joseph and Ian manage the best introduction to general systems thinking I've seen anywhere in the NLP community.