The Exodus Guide is a more detailed overview of Exodus 90. It gives you the history of the program’s development, offers practical advice for how you can best prepare for the experience, and includes encouragement from the lives of the Saints (especially the Early Church Fathers) and the Catechism of the Catholic Church. The 90 meditations of Exodus are also compiled here.
A more-than-challenging prayer & ascetic programme, not only due to the difficulties of its requirements but also because of its sheer length - a real journey in the wilderness, with physical hardship, little water, tasteless food, and no entertainment. We're all tempted to despise the weakness of the Israelites when they fail and complain to God again, and again, and again, and yes, I knew intellectually that I shouldn't because I am also weak, but through this programme I actually experienced my weakness and have seen them exposed constantly as never before. A good prayer & ascetic programme is a one that makes you more dependent on the grace and mercy of God, and a high bar is therefore indispensable. Indeed, I would rather set my Lenten target on the moon and then fail and become more humble, than determining not to eat chocolate for 40 days and then succeed and pat myself on the shoulder.
Although, all of these being said, dear Catholic (and other Christian) brothers, never give up hope of attaining true freedom in this world, otherwise Christ would not have demanded us to "be you therefore perfect, as also your heavenly Father is perfect" (Matthew 5:48). God does not make unreasonable demands. The humanly mission impossible becomes truly possible when we are rooted in Christ, the true vine that yields many fruits. When the day is far spent and night approaching, may all of us be able to say with St. Paul: "I have laboured more abundantly than all they: yet not I, but the grace of God with me" (1 Corinthians 15:10).
I read a second edition of this book revised by Nathaniel Binversie. Exodus 90 is a 90 day spiritual exercise focused on three key themes: prayer, asceticism, and brotherhood. For each of the key themes participants are to complete different tasks daily or weekly. For example, for prayer one is to do a day holy hour with at least 20 minutes silent prayer. Along with completing the daily spiritual exercises, which the book outlines in the beginning, each day includes a devotional reading that walks through the Bible book of Exodus. The readings provide parallels of the Israelite journey out of Egypt into the Promised Land with the Christian (Roman Catholic) faith, as well as stressing particular reasons for the prayer, asceticism, and brotherhood exercises. The book is easy to read, and was actual converted into a smartphone app. However, the exercises are quite the challenge but are quite rewarding to complete.