The Overlanders' struggle to develop war technology in time to repel the feared attack is gripping, as is the technology itself - with only a few fictional elements (the unusually hard wood brakka and the two crystals that produce a reaction) this is a pre-steam medieval space opera and war novel. Part of the fascination is seeing these astronauts master space travel without knowing any Newtonian physics and the wrong-headed assumptions that they make as a result. Having said that, once the Land forces do appear on the scene the action is anticlimactic as the Overland forces are a little too well prepared and lucky, and always stay several steps ahead.
The book also feels as if two novels have been squeezed into one - the last third of the novel deals with a journey to the system's third planet, Farland, to resolve a paranormal mystery described in interludes throughout the earlier chapters. With a little more balance between sides in the war, and perhaps a longer, more in-depth exploration of Farland, both could easily have been fascinating stand-alone novels. The story of Overland continues in a third novel, The Fugitive Worlds.