There are three groups of Men in Tolkien's works: the High, Middle, and Low.
The High Men are those who are truly descended from Westernesse, now through Isildur's lines or those of a few other Númenorian survivors.
There are also throwbacks to the High Men of old, notably Faramir and Denethor of
Gondor. Those that Tolkien characterizes as
High Men possess the ability to look both out into the world beyond and into the hearts
and minds of those around them in a manner that other Men cannot do. They are strong,
long-lived, and fierce fighters, but do not value battle, but knowledge, and do not seek
after glory from a warrior's deeds unnecessarily.
The Middle Men are made up of the Riders of Rohan,
the Men of Dale and Laketown, many who live in Gondor in the latter days, and others. By
and large good men, they value valor above many things, and do not treasure knowledge and
learning in the same manner as the High Men, although it is not ignored either. Rather,
they are more pragmatic than their nobler peers, and have less patience for things that
lack immediate value in an often harsh world.
The Low Men consist of two distinct groups. The first are the uncultured savage tribes
who are scattered over Middle Earth, but are essentially good. The Wild Men led by
Ghan-Buri-Ghan are an example. They wish only to be left alone to pursue their own ways,
and are not inherently a part of Tolkien's moral play. The other class of Low Men are
those who are allied with Sauron or under his sway. These Men
are sometimes closer to the Middle Men in behaviors; as some of the Southron tribes fight
in a manner reminiscent of the Rohirrim, but in Tolkien's view, an alliance with evil
seems to cancel out any virtue a group or individual may have previously had, although he
does not place them beyond salvation.