Konrad Zuse’s 1969 book “Rechnender Raum”

Zuse was the first to propose that physics is just computation, suggesting that the history of our universe is being computed on, say, a cellular automaton. His “Rechnender Raum” (Computing Cosmos / Calculating Space) started the field of Digital Physics in 1967. Today, more than three decades later, his paradigm-shifting ideas are becoming popular.

The Universe is a Computer

Calculating Space (Book PDF)