In this volume the authors translate and annotate key passages from ancient authors to provide a history and an analysis of the origins and development of technology.
As a historical overview of Greek and Roman technology, Humphrey's sourcebook is full of wonders. Ancient vending machines that dispensed cups of water. Giant water screws and other hydraulic devices. Steam-powered door chimes that announced visitors to temples. Portable sundials: the ancient version of the modern wrist-watch. Even a low-tech pedometer which calculated the distance traveled by wagons. The information is presented in excerpts of Greek and Latin texts. At times, I would have liked a bit more detail on certain inventions, but the sourcebook aims for breadth. It even treats the contentious subject of automata within the ancient world, an innovation which remains shrouded in mystery (did emperors really have tiny robot animals, or giant, mechanical representations of the gods?) It can't really be proven, but the sourcebook doesn't completely discount it (a fact that pleased the fantasy-writer in me).
The authors provide a great number of translations from Greco-Roman antiquity regarding technology in broad sense. About half of the volume comes from well-known and readily available sources such as Pliny the Elder and Vitruvius.
Just remember, it is a sourcebook, and as such, it is not really a self-standing volume. A good way to understand it is as a companion volume to the Oxford Handbook of Technology in the Classical World or a similar book. By itself, it has a number of issues: the sources are not rated by trustworthiness (the book includes obvious propagandizing and urban legends right next to the most reliable sources we have), the geographic and temporal locations are wildly mixed from one translation to another, no textual analysis is included even in long segments, and most importantly, there is no discussion of the limitations of the whole textual heritage. For example, if you are interested in the question whether Mediterranean sailors used nontrivial celestial navigation, all you can see is that there is no source in the book addressing that, and with that you are left on your own.
A fairly deep knowledge of the timeline of antiquity, its geography, and main writers is a prerequisite, because the book is a jungle in this respect and the authors spend no time explaining the context.