"Project Mars" answers a burning question long posed by serious students of aerospace history: "What in the world did Wernher von Braun do for those five long years between 1945 and 1950 while he was cooling his heels in near-isolation at Fort Bliss, Texas?" The answer is that, among other things, he wrote this book.
"Project Mars" is a fictionalized tale about the first manned expedition to the Red Planet. As a science fiction novel, it has little to recommend it. Its stodgy style, tortured dialog passages and primitive narrative structure are even worse than most other contemporary books of the genre--which did not set the bar very high themselves. For example, have you ever heard a real person use the word "obstreperous" in ordinary conversation? Some of this may, of course, be due to its translation from German into English, but, even so, "Project Mars" is a breathtakingly bad novel. It's easy to understand why it languished in unpublished limbo for 60 years.
However, as a detailed technical description of the hardware, operational concepts and design challenges involved in mounting a massive ten-spacecraft Mars expedition, firmly grounded in the knowledge and engineering techniques available in the late 1940s, "Project Mars" is a superb and important historical document. Remember that, when von Braun wrote it, Sputnik I, the first artificial Earth satellite, was still 10 years in the future. At that time, very few people took seriously the idea of "men" journeying into space. The very thought of a mission to another planet was laughable. "Project Mars" is, in essence, a primer on elementary spaceflight concepts for readers who had never heard of such a thing before. The exhaustive, excruciatingly detailed descriptions of the spacecraft, the orbital trajectories, the mission timelines, the mass budgets and so on were thus necessary to convince readers that such an expedition was technically feasible. Unfortunately, we'll never know if it would have had the intended effect, since it did not see the light of day until long after spaceflight became "routine."
All things considered, I rate "Project Mars" with four stars because of its depth, scope and historical significance. Its magnificent, exquisitely printed Chesley Bonestell paintings alone are nearly worth the price of admission. It should appeal to readers with a real interest in finding out what one of the two greatest rocket engineers of the 20th century (the other being Sergei Korolev) thought about the future of the technology he developed. But "Project Mars" is pretty deep and very technical, so casual readers will probably want to give it a pass.