These three books – perhaps more than any others – are the beginning of practical life sciences.

These men, empowered by their societies, showed that our human brains can observe the natural world, understand it in new ways, communicate it to others and then perceive collectively of the complicated idea of natural selection over eons being responsible for the evolution of all life.

These books are the beginnings of our contemporary understanding of deep time in relation to living things, the dawn of bio-geographical studies.

Alexander von Humboldt’s Personal Narrative of a Journey to the Equinoctal Regions of the New Continent influenced the young Charles Darwin profoundly.

Alfred Russell Wallace shares more in common with von Humboldt though. His independent spirit and commitment to observation and collection of species was a titanic extension of the thinking.

Evolution is real. Natural selection is real. It’s happening constantly all around us and has been since the dawn of time.

These men were the first to describe it on a scale that makes it visible and comprehensible to all who read them.