Coloured Book
The British academic protocol suite that ran over X.25, named after the colours of the binders its specifications came in.
In the late 1970s British universities wrote their own protocols rather than wait for OSI to be finished — or commit to ARPANET's American TCP/IP. Each layer got a colour: Yellow Book was transport, Grey Book mail, Blue Book file transfer (NIFTP), Green Book terminal access and Red Book remote job submission.
The suite carried JANET from 1984 and worked, but in isolation. Grey Book wrote domains big-end first, uk.ac.cam, so every message to the internet had to be flipped in a gateway. Once JANET opened its IP service in 1991 the matter was settled, and the books were phased out over the following years. They were meant as a bridge to OSI; OSI never arrived.