Coxeter groups, Hecke algebras and their representations -- Applications of Kazhdan-Lusztig theory -- Geometric interpretations of the Kazhdan-Lusztig polynomials -- The algebraic descriptions of the affine Weyl group An of type Ãn?1, n>2 -- The partition of n associated with an element of the affine Weyl group An -- A geometrical description of the affine Weyl group An -- Admissible sign types of rank n -- Iterated star operations and interchanging operations on blocks -- The subset ??1(?) of the affine Weyl group An -- The set N ? of normalized elements of ??1(?) -- The orbit space Ãn of the affine Weyl group An -- The sequence ?(w,k) beginning with an element of N ? -- Raising operations on layers -- The left and right cells in ??1(?) -- ??1(?) is an rl-equivalence class of An -- Left cells are characterized by the generalized right ?-invariant -- The two-sided cells of the affine Weyl group An -- Some properties of cells and other equivalence classes of An -- Some special kinds of sign types -- The inserting algorithm on the set C -- The restriction of the map on p n.