A Protocol for Packet Network Intercommunication Alive
TCP — the protocol paper that made internetworking possible, proposing a common envelope across unlike networks. TCP/IP split from it in 1978.
Published in IEEE Transactions on Communications in May 1974, the paper proposed gateways connecting heterogeneous packet networks, and a Transmission Control Program providing reliable end-to-end byte streams between processes — the internetwork idea, not just another network.
The 1978 split into TCP (reliable) and IP (routing/best-effort) produced the modern protocol stack. Cerf and Kahn are the internet's official parents for it; both were later awarded the Turing Award (2004) and the Presidential Medal of Freedom.