Merton wrote this book not as a history of the early Desert Fathers or as a selection of their writings, although it incorporates both these elements. Rather it is a selection of texts compiled for friends out of his own contemplative experience. In encountering the writings of the Desert Fathers he compares their spiritual environment to that of the modern world, and offers a selection of extracts from their writing that have proved useful for him in contemplation.
Having read the thoughtful introduction to the selected extracts, I took several months reading the extracts themselves. My method was to read one, turn it over in my head and let it dwell there until I felt that I knew what it was saying to me, and then move on. I spent several days on each extract - with a lot of distractions! People will encounter this book in their own ways though: as something you read very quickly and then come back to later, or as a resource to turn to for prayer or inspiration when you are feeling dried out and lacking in energy or inspiration.
I highly recommend the book as a resource for anyone seeking to engage with the world and themselves more reflectively.