Xerox System Integration Standard - Internet Transport Protocols (aka the "Gray Book")

My friend and colleague Mike Peltzer found this on the NextSpace free counter this morning.  Back when I was a lad at 3Com this was my bible for about 6 months.  Known as the Xerox "Gray Book" it is officially titled Xerox System Integration Standard - Internet Transport Protocols (Xerox, Stamford, 1981). The book specifies the core protocols of the Xerox Network Systems (XNS) protocol suite. Among other things I used it to implement the Sequenced Packet Protocol (SPP) on Mac OS. I'm happy to have this fine, thin volume on my work bookshelf in the nostalgia section.