Integer maps, or fxmappings, are finite sets, where each element is an association between a fixnum (exact integer) key and an arbitrary Scheme object. They are similar to the general mappings of SRFI 146, but the restricted key-type allows implementations of fxmappings to benefit from optimized structures and algorithms. This library provides a rich set of operations on fxmappings, including analogues of most of the forms provided by SRFI 146. Fxmappings have no intrinsic order, but may be treated as ordered sets, using the natural ordering on keys; a substantial sublibrary for working with fxmappings in this fashion is included.