The product is a vintage paperback textbook titled "The C Programming Language" by Brian Kernighan and Dennis Ritchie. Published in 1978 by Prentice Hall PTR in the United States, this classic book serves as a fundamental reference for those learning the C programming language. Written in English, this textbook provides a comprehensive introduction to the C programming language and is widely considered a must-have for anyone interested in software engineering and computer programming. Its timeless relevance and iconic status in the world of computing make it a valuable addition to any programmer's library.