Alpine
Alpine is a free software email and news client developed at the University of Washington. Development at UW ended in 2009, but new releases are maintained by Eduardo Chappa and hosted at: http://alpine.x10host.com/
For history about Alpine and a brief overview of its features, see https://en.wikipedia.org/wiki/Alpine_(email_client)
For history about its predecessor Pine, see https://en.wikipedia.org/wiki/Pine_(email_client)
This page links to information regarding installing and setting up Alpine on your local machine, along with importing your address book from pine.gl.umbc.edu.