This is an omnibus of 3 short novels by Heinlein, published around 1965. The novels are "The Puppet Maters" (1951), "Waldo" (1942), and "Magic, Inc." (1940). I read the unexpurgated version of "The Puppet Masters" (1990), which I would say is the recommended version to read. Of the three novels in this volume, "The Puppet Masters" is the most substantial in plotting, character, and thematic exploration. It is one of several stories published in the 1950s allegorizing communism in the form of aliens with collective intelligence who take over the bodies of humans (or the only humans that mattered in American science fiction - Americans) and use them for evil purposes. These aliens are collective intelligences, hence representative of the communist menace and the supposed fifth columnists. The narrator is an operative for a nameless secret government agency that gets involved tracking down the invasion. In a way, it is a kind of spy novel, complete with brain-washing (i.e. the slugs latch on and take over one's mind), double-agents, chases, daring rescues, and so on. It is highly entertaining, but also somewhat philosophical as Heinlein takes some time to explore the implications of the scenario he has created. This novel is also one of the earliest in which Heinlein indulges some musings on the nature of the sexes, on what is "essential" to men and women. Some of these ideas are by today's standards infuriatingly out-dated and so over-the-top sexist that the conversations in which they occur are difficult to get through. The infuriating part is that Heinlein believes he is being fair and honest and treating the sexes equally. These can be skipped over, however, as they are not essential to the plot and the main problem that Heinlein engages in. "Waldo" is famous for an idea, one of several, central to its plot. That idea is the use of remote-controlled robots, and more particularly, remote-controlled robots used to create ever-smaller remote-controlled robots. It is a precursor idea for how one can build nanotechnology, even though even in 1942, the whole concept was a logical extrapolation of existing technology. This story is chock full of technological ideas: a nation-wide power grid based entirely on broadcast power rather than wired power, life in zero gravity as a means to allow a person with a physically debilitating disease to have something like normal freedom of movement, personalized space ships, and so on. It also has one big speculative science idea - a parallel universe in contact at all points with our universe, and from which one could defeat the law of entropy by stealing power. The story itself proceeds as a typical hard-science story revolving around engineering problems - the power condensers for broadcast power are randomly failing, and humans seem to be getting weaker physically and mentally. The "trick" of the story is that the solution to these problems is in essence magic, presented in scientific and engineering terms. From the science and tech side, it is all rather interesting. The story itself is a little less so, relying to a great extent on that old stereotype of the lone genius. Also, the high-tech future is very much a man's world; there is not a single woman in the story, not a wife, mother, sister, cousin, co-worker, or female human of any kind (there is one female bird). Again, it is quite entertaining in many respects. "Magic, Inc." is the lightest of the three, a jolly jape in which the extrapolative idea is to have the world be pretty much as it is, except that magic is a profession and magic really works. Someone is using dirty tricks to corner the magic market, create a monopoly, and ruin both business and labor. There is a bit of free-market libertarianism in Heinlein's thinking, but fortunately in this story he does not push it too hard. Instead, this one is an "entertainment" full of unlikely characters forming an improbable team to go against an impossible enemy. The collection in total is on the lighter end of Heinlein's prodigious output, although "The Puppet Masters" was highly rated among science fiction critics at one time. Nowadays, it is perhaps more rightly seen as a work of its time. Definitely, Heinlein has written deeper and more sophisticated works, most of which were published after these. However, these show that Heinlein could also be a very good entertainer.