Prosanta encourages us to think of life as being like a book, one that is always in the making. What we see living around us today are just the last few pages. If we look out on to the millions of species that we share this planet with we can trace their histories, and ours, back through nearly four billion years of evolution. We can also think of all the living things around as the young leaves on an ancient and gigantic ‘Tree of Life,’ all of us connected by invisible branches not just to each other, but to our extinct relatives and our evolutionary ancestors.