At different points in his books, Daniel refers at some length to the following sources from the eastern church:
Isaac the Syrian.
Macarius the Great.
Maximus the Confessor
Sentences of the Desert Fathers (Alphabetic and Systematic)
A very fine modern author with the eastern background, whom it would be hard to recommend too highly (and is noted by Bob Ekblad) is Matthew the Poor (Matta El-Meskeen), an Egyptian Coptic monk, whose writings, while drawing deeply on ancient eastern sources, are very well attuned to the modern world and speak most directly to our western church. His books in English are really superb and line up particularly well with Daniel in the way he cites the Church Fathers. Orthodox Prayer Life is particularly good in this respect.
In order to gain insight into the eastern, Orthodox church, an introductory work I found immensely helpful is The Orthodox Way by Kallistos Ware. How much deeper and more satisfying is the theology found here than the sort of thing I was taught at bible college! I was personally well prepared to investigate this sort of teaching; I studied 6 years of Russian language at school, and later had an elderly Russian friend who was born in 1900, fled Russia in 1917 and eventually found her way to England; as a child, she told me, she had been prayed for by John of Kronstadt, a wonderfully godly man. The orthodox style of Christian faith has great strengths. Another theological type book I found useful was The Mystical Theology of the Eastern Church by Vladimir Lossky; to my surprise, it turns out that in most of the literature the word mystical tends to mean experiential and practical.
On the theological front, TF Torrance may also prove helpful. Torrance, a Scotsman, sought some rapprochement with the the thinking of the eastern and early Church; he’s very good on salvation, incarnation etc. This is serious theology!
Readers might prefer more personal accounts! A lovely book giving expression to Orthodox practice in modern day Greece is Wounded by Love (The life and wisdom of Saint Porphyrios). Styled a saint in the title, this was just a very godly Greek Christian within the tradition prevalent in his country. Along with his life in busy Athens, he describes Mt Athos and its monks; there is also much sage doctrine/advice. (The chapter On the upbringing of children is superb.)
In connection with Porphyrios, other very fine books, by which I mean inspiring, are various books and a biography of Elder Paisios. This man led a remarkably influential life in his native Greece; like Porphyrios, he is very recent and understands very well the difficulties of modern life, so that despite the foreignness of the monastic life he speaks very clearly to our society. In fact, I cannot speak too highly of his Spiritual Counsels, 5 volumes which I have read right through at this point 3 times. (A sixth, On Prayer, has now been published.) At times they have interesting biblical reflections, but mainly they have to do with Christian character, growth in virtue. Paisios’ spiritual father, so to speak, was a man named Arsenius, who was pastor to a Greek village in Cappadocia prior to their forced removal to Greece; Paisios produced a biography/study of this man which is as remarkable an account of new testament pentecostal ministry as you could wish to read.
A non-Protestant, French work which quotes Daniel, also translated by myself and available in English, is Evangelizing the Depths by Simone Pacot. I have added a page to this website on her books.
I would like to add a further note here about the Orthodox church. I personally have had a struggle with the doctrines to do with penal substitution as frequently taught in western, American influenced churches; as part of my reading around this subject, I encountered a book by a then Orthodox “priest,” Joshua Schooping titled An Existential Soteriology and this was a work I found very helpful, setting both the penal and the substitutionary ideas in church father type writings which express the ideas in ways I found most illuminating. Schooping has subsequently left the Orthodox church, and his reasons for doing so are laid out in another work Disillusioned. He doesn’t discount the good theology, though he does say that he has found “Protestant” theology much better (my summary); rather, he decries areas such as Orthodox ecclesiology and particularly its mariology and iconography. I think it’s important to express this note of caution. However, throughout the Orthodox writings I have looked at, together with Daniel, there is an emphasis on humility that seems sadly lacking from church life as I have too often experienced it.