This package computes the integral closure of type I affine domains using the qth-power algorithm from D.A.Leonard, Finding the missing functions for one-point AG codes, IEEE Trans. Inform.Theory, 47(6), 2001, pp. 2566-3573, D.A.Leonard and R.Pellikaan, Integral closures and weight functions over finite fields, Finite Fields and Their Applications 9(4), 2003, pp. 479-504, D.A.Leonard, A weighted module view of integral closures of affine domains of type I, Advances in Mathematics of Communication 3(1), 2009, pp. 1-11. (icFracP in the IntegralClosure package of Macaulay 2 and normalP in Singular's normal package are attempts to generalize this by ignoring all of the structure that is required by this package in order to produce similarly structured output.) Also this package contains the extension to examples over the rationals; which, in turn, allows for quicker answers over ZZ/q for most large q.