  In this article we introduce the categories of noncommutative (mixed) Artin
motives. In the pure world, we start by proving that the classical category
AM(k) of Artin motives (over a base field k) can be characterized as the
largest category inside Chow motives which fully-embeds into noncommutative
Chow motives. Making use of a refined bridge between pure motives and
noncommutative pure motives we then show that the image of this full embedding,
which we call the category NAM(k) of noncommutative Artin motives, is invariant
under the different equivalence relations and modification of the symmetry
isomorphism constraints. As an application, we recover the absolute Galois
group of k from the Tannakian formalism applied to NAM(k). Then, we develop the
theory of base-change in the world of noncommutative pure motives. As an
application, we obtain new tools for the study of motivic decompositions and
Schur/Kimura finiteness. Making use of this theory of base-change we construct
a short exact sequence relating the absolute Galois group of k with the
noncommutative motivic Galois groups of k and of its algebraic closure.
Finally, we describe a precise relationship between this short exact sequence
and the one constructed by Deligne-Milne. In the mixed world, we introduce the
triangulated category NMAM(k) of noncommutative mixed Artin motives and
construct a faithful functor from the classical category MAM(k) of mixed Artin
motives to it. When k is a finite field this functor is an equivalent. On the
other hand, when k is of characteristic zero NMAM(k) is much richer than MAM(k)
since its higher Ext-groups encode all the (rationalized) higher algebraic
K-theory of finite etale k-schemes. In the appendix we establish a general
result about short exact sequences of Galois groups which is of independent
interest. As an application, we obtain a new proof of Deligne-Milne's short
exact sequence.
