Source : Webster's Revised Unabridged Dictionary (1913)

Vade mecum \Va`de me"cum\ [L., go with me.]
   A book or other thing that a person carries with him as a
   constant companion; a manual; a handbook.

Source : WordNet®

vade mecum
     n : a concise reference book providing specific information
         about a subject or location [syn: {handbook}, {enchiridion}]