Basically a must-read for anyone interested in late antique Syrian asceticism, or early Christian asceticism in general. This is probably the best single document of Syrian monasticism in the fourth and fifth centuries, so as a historical document it's indispensable. Price has a thorough introduction and has carefully annotated each chapter, even including a highly useful chart in his introduction mapping the structure of the text and two separate indexes of names mentioned and subjects (ascetic practices, miracles, diet, language, cenobitic institutions, etc.) which are surprising to find but actually quite helpful.
As for the text itself, it's great fun if you're into hagiography and asceticism. Syrian eremetic monks were pretty balls-to-the-wall when it comes to that, so get ready for some primitive stuff--eating grass, literally living in one's grave, living on a pillar, cave-dwelling, self-starvation, summoning animals, etc. It's pretty cool that Theodoret traveled around and visited these people himself, and even for the older ones who had died by the time he was writing this he would visit their institutions (if they had established one,such as Publius) and talk to people who did know them. These were the people Theodoret held up as not only inheritors of the Apostolic tradition, but also as "philosophers" who beat the Hellenistic philosophers at their own game. Symeon Stylites is definitely the most well-known here, as the other reviewer has noted. If you're interested in him, I also recommend checking out Robert Doran's translation of his Lives, which includes the Syriac panagyric written by his disciples and the mysterious (and very popular in premodern times) Life by Antonius as well as the one present in this volume. If you're coming to this as an academic, you don't need my review to buy this. Otherwise, it's got some great stories for the adventurous reader or I'd imagine for the religiously-inclined as well (though I don't think it was the writer's intent that we should imitate these acts, there is some serious mortification going on here).