A polynomial skew product of C is a map of the form f(z, w) = (p(z), q(z, w)), where p and q are polynomials, such that f extends holomorphically to an endomorphism of P of degree ≥ 2. For polynomial maps of C, hyperbolicity is equivalent to the condition that the closure of the postcritical set is disjoint from the Julia set; further, critical points either iterate to an attracting cycle or in...