This Masterwork Index is of no value without a set of Irwin Schiff's published materials - at least of "The Federal Mafia." In case as you use ISMIS you find you need more of those materials, call (800) TAX-NOMO or, if The Ban is in force, post a Wanted Ad on SSC.
A recommended set of foundational works is shown here - it costs much less than would be recovered in saved taxes by most students in under a month.
ISMIS has little value for the academic, uncommitted visitor; it is intended for those implementing his procedures. Otherwise, there are no prerequisites.