Ping? -- seldom does humor, software, China and ducks converge so well as this book review: Excellent, heart-warming tale of exploration and discovery. Using deft allegory, the authors have provided an insightful and intuitive explanation of one of Unix's most venerable networking utilities. Even more stunning is that they were clearly working with a very early beta of the program, as their book first appeared in 1933, years (decades!) before the operating system and network infrastructure were finalized. be sure and scroll down to picture of the yellow fuzzy duck