Recently, I have been working on a new book called The Cosma Hypothesis. It builds on The Overview Effect, which focuses primarily on our relationship with the Earth in space, and considers our relationship with the universe (Cosma).
Underlying all of this work is the effort to develop a coherent "philosophy of space exploration." At this point, the main breakthrough is to consider this new philosophy to be non-anthropocentric, i.e., aimed at understanding how humans can benefit the universe as well as how the universe can benefit us (the latter being the starting point for most justifications for space exploration and development.)
Slowly but surely, we are beginning to understand that we are part of an ecosystem, which is defined as: