BBDB is the Insidious Big Brother Database for GNU Emacs. It provides an address book for email and snail mail addresses, phone numbers and the like. It can be linked with various Emacs mail clients (Message and Mail mode, Rmail, Gnus, MH-E, Mu4e, VM, and Wanderlust). BBDB is fully customizable. WWW: http://savannah.nongnu.org/projects/bbdb/