The Internet School of Orthodox Studies Spring 2001 semester is intended to serve as an introduction to the three major liturgical cycles of Orthodox Worship with special emphasis given to the catechetical emphasis of each cycle. This series is presented by Rev. Dr. Frank Marangos.

Established by the Department of Religious Education in 1998, ISOS ran through the Fall of 2005 as a means to assist Orthodox Christians to better understand the teachings of the Orthodox Church. These classes have all been archived on the goarch.org website with the assistance of the Archdiocese Department of Internet Ministries.