The article explains how TCP (Transmission Control Protocol) makes internet communication reliable despite the underlying network being unreliable, with packets getting lost, corrupted, or reordered. TCP handles flow control, congestion control, and error recovery automatically, allowing developers to build applications like websites and email systems without worrying about these low-level networking issues. The author provides C code examples showing how to create simple TCP servers and explains the basic socket programming functions like bind, listen, accept, and send that make reliable network communication possible.