Although school funding structures are similar in many ways across the states, no two states have school finance systems that are precisely the same. School finance systems which are used to achieve multiple objectives, must consider characteristics of numerous school districts, distribute large amounts of money, and have developed incrementally over long periods. Given the multiple goals that every state's school finance system is trying to achieve and the large number of districts such systems must consider, it is not unexpected that they would be somewhat complicated. In most states, there are few legislators, legislative staff, educators, academics, and the general public who are familiar with the intricacies of school finance. This document functions as a guide to understanding the complexities of school finance systems, in an effort to encourage more policy makers to become familiar with and to take an interest in school finance. It contains a quick lesson in the development of school finance systems, a brief overview of the goals on school finance systems, a short discussion of the relationship between the structure of school finance systems and school finance litigation, and an organized description of the various components of school finance systems. Examples use simple arithmetic and describe the various calculations undertaken. A glossary is appended. (LAP)