This document was prepared to assist users in the cost modeling of space systems using the SEER product suite: SEER-H, SEER-SEM, SEER-IC, and SEER-EOS. The information which constitutes this document has been developed and created through modeling and the validation of hundreds of space systems of many types. This document also includes the practical knowledge of the Galorath staff with many years of experience in working with space projects. Most recently, this guidance has been enhanced through the efforts of various NASA-sponsored validation studies. These workshops have helped validate many of the modeling approaches as well as enhanced the current model and modeling practices. However, judgment should still be exercised when modeling to ensure that the recommendations are appropriate.