Normal bases of affine PI-algebras are studied through the following stages: essential height, monomial algebras, representability, and modular reduction.In this survey we review the algorithmic theory of PI-algebras, in terms of normal bases, and indicate directions for further research. In view of Kemer [15], one can study normal bases in terms of the codimension theory of PI-algebras, of which Regev is the pioneer. This topic is developed in [10,19]. Thus we feel this paper is appropriate for a volume honoring Regev.Let A be an associative affine algebra over an infinite field k, generated by the set Ω = {a 1 , . . . , a }. Ordering the letters a 1 < · · · < a induces the lexicographic order on the set Ω * of words in the generators over the alphabet: w < v if |w| < |v|, or if |w| = |v| and w is lexicographically smaller than v. The normal base of the algebra A with respect to the ordered set Ω, is the set of all words in Ω * that cannot be written as a linear combination of smaller words [4,9,24]. Obviously this is a base of A (as a vector space).