To begin your reading in the Scriptures, it is highly recommended to use the Orthodox Study Bible, providing quotations and commentaries from the Early Church Fathers.
Thirsting for God in a Land of Shallow Wells, by Matthew Gallatin
INTRODUCTION TO THE COPTIC ORTHODOX CHURCH, by Fr. Tadros Malaty
Orthodox Thought and Instruction: In the Orthodox Church, by Fr. Tadros Malaty
THE ORTHODOX CONCEPT: TRADITION AND ORTHODOXY, by Fr. Tadros Malaty
THE SEVEN SACRAMENTS: The Catechism of the Coptic Orthodox Church - Book III, by Fr. Tadros Malaty
COPTIC CHRISTOLOGY PAST AND PRESENT, by Fr. Tadros Malaty
GOD: The Coptic Orthodox Church & The Dogmas, by Fr. Tadros Malaty
THE COPTIC ORTHODOX CHURCH & THE DOGMAS: ALEXANDRIA AND CHRISTIAN DOGMAS, by Fr. Tadros Malaty
Becoming Orthodox: A Journey to the Ancient Christian Faith, by Fr. Peter Gillquist
Comparative Theology (Free PDF), by H.H. Pope Shenouda III
For the Life of the World: Sacraments and Orthodoxy, by Alexander Schmemann
Salvation in the Orthodox Concept (Free PDF), by H.H. Pope Shenouda III
The Inner Kingdom, by Bishop Kallistos Ware
The Faith: Understanding Orthodox Christianity, by Clark Carlton
The Orthodox Faith (Free PDF), a compilation of writings by the SUS Diocese. Topics include Holy Tradition, Theology, Christology, and other topics.
The Orthodox Church, by Timothy Ware
These books are available in PDF for free:
Introduction to the Coptic Orthodox Church, by Fr. Tadros Malaty
Understanding the Liturgy, by Fr. Athanasius Iskander
Beginning to Pray, by Anthony Bloom
Orthodox Prayer Life: The Interior Way, by Matthew the Poor
Preserve them, O Lord by Father John Mack
Two Become One: An Orthodox Christian Guide to Engagement and Marriage by Father Antonios Kaldas
Parenting Toward the Kingdom, Orthodox Principles of Child-Rearing, by Philip Mamalakis
Blueprints for the Little Church: Creating and Orthodox Home, by Elissa Bjeletich and Caleb Shoemaker
Bringing Up Girls, by James Dobson
Bringing up Boys, by James Dobson