Vade mecum : A book or other thing that a person carries with him as a constant companion; a manual; a handbook.

Example:


Taxonomy
Vade Mecum, the Pocket PC, VM, Plucker Desktop, Konstantin, Henrik, eBook readers, bugs, new features, Jamis Buck, processor, alpha release, 1 May, document viewer, Shots, charsets, Chris Berry, Vade-Mecum.

Defination from the web:
Vade Mecum (pronounced "VAY-dee MEE-cum", which is Latin for "go with me") is the first-ever Plucker document viewer for the Pocket PC. ... Vade Mecum's primary goal is 100% feature compatibility with the official Plucker viewer, which means it will be able to view any Plucker ...