In 1964 Paul Baran of the Rand Corporation, Santa Monica, California, wrote On Distributed Communications: I. Introduction to Distributed Communications Networks, describing the use of redundant routing and message blocks to send information across a decentralized network topology.
"One in a series of eleven Memoranda detailing the Distributed Adaptive Message Block Network, a proposed digital data communications system based on a distributed network concept. It introduces the system concept and outlines the requirements for and design considerations of such a system, especially in regard to implications for its use in the 1970s. In particular, the Memorandum is directed toward examining the use of redundancy as one means of building communications systems to withstand heavy enemy attacks" (https://www.rand.org/pubs/research_memoranda/RM3420.html)
Baran's paper was published for consumption by the engineering public in IEEE Transactions on Communications Systems, 12, No. 1 (March 1964) 1-9.