In this setting, travel to other worlds is possible but not easy, and is supervised by an organization called Viagens Interplanetarias.note Several planets with intelligent life have been found; many of the stories feature the planets humans call Krishna and Vishnu, orbiting the star Tau Ceti.
The mode of the stories is an attempt to reconstruct Space Opera and Planetary Romance with more realistic premises: thus, a human may have an adventure in which he and a scantily-clad alien princess fall in love, but they're not going to be able to have children and he didn't get to her planet using any kind of hyperdrive or teleportation.
This series contains examples of:
- Alien Non-Interference Clause: Terrans are specifically forbidden from importing technology to the warlike inhabitants of the planet Krishna. Enforcement of the rule is done by electronic brainwashing so that even if the natives capture and torture a visitor, they are unable to reveal anything. Note that clever ways to evade this rule drive the plots of several stories.
- Arranged Marriage: The Krishnans practice arranged marriage, a fact that upsets the occasional human that falls in love with one. However, in nearly all cases the Krishnans themselves are totally unbothered by arranged marriage, as they consider marriage to be an important lifetime social and financial arrangement too important to be dictated by something as fickle and ephemeral as love. Several characters even express horror of the very idea of marrying for love.
- Bee People: Rogue Queen features the Ormazdians, a race of medieval-age humanoid monotreme aliens who have a fairly scientifically accurate hive society with egg-laying queens, sterile female workers, and male drones who only live to fertilize the queen. There is also a subspecies that has both worker and soldier females. The Ormazdians' sexual development is triggered by meat proteins, so the queens explicitly forbid workers from eating meat, claiming that it will poison them. Naturally humans arrive on Ormazd, help some workers they've befriended discover the truth, and destroy the entire Ormazdian societal structure. This is portrayed as ultimately for the best, as the hive society causes stagnation. (The Ormazdians should not be confused with the Krishnans, who are also medieval-age humanoid monotremes but do not live in a hive structure.)
- Body Paint: One of the humanoid cultures on planet Krishna lives in such a hot climate that the people forgo clothing altogether, and only wear jewelery and body paint.
- Boldly Coming: In The Hostage of Zir, one of the characters comments that The Bible forbids fornication(sex with a human you're not married to), and bestiality(sex with an unintelligent animal). But there Ain't No Rule about fun with a Green-Skinned Space Babe on the planet Zarathustra.
- Enforced Technology Levels: The planet Krishna has a generally Medieval level of technology, and human visitors have to have psychological blocks implanted in their minds to prevent them from changing that. It's not so much to protect the locals as to protect other planets from the Krishnans, who have all the unpleasant habits of feudal societies — vicious misogyny, chattel slavery, killing people for insulting them — stuff that would be catastrophic if practiced with spacefaring technology. Several of the stories center on innovative ways to get around this restriction, as they make it clear that they'd trade a lot of gold for weapons to kill their enemies. A particularly clever one is a parrot trained to dictate technical manuals when the Trigger Phrase is spoken.
- It's even acknowledged In-Universe to be really controversial; when the ban was first proposed, liberal factions were able to squeeze in loopholes for humanitarian technologies such as medicine, sanitation, agriculture, etc. Within several years Kirshna became a really Adventure-Friendly World; the first kingdom to adopt these technologies turned its healthier populace into an army and proceeded to invade and conquer a number of neighboring nations - and within a decade, similar wars had broken out everywhere. The ban became total afterwards, with no plans to teach new technologies for the foreseeable future.
- Exotic Equipment: The planet Krishna has a race of humanoid monotremes that, while anatomically similar to (but not interfertile with) humans, take considerably less time to climax. For this reason female Krishnans tend to seek out male humans for liaisons, while female humans try to avoid male Krishnans. It's also worth noting that, while humans last longer, male Krishnans were capable of copulating much more often (15-20 times per night).
- Green-Skinned Space Babe: Krishna is populated by a humanoid species that happens to be sexually compatible with humans (though matings won't result in offspring). Some of them wear nothing but jewellery and body paint. Needless to say, one of the human characters gets to seduce a local princess. (The Krishnans are actually depicted as green-skinned humanoids in the GURPS adaptation of the setting.) De Camp knew exactly how unlikely this would be, but wanted to write swashbuckling, two-fisted adventure stories IN SPACE!, and worked very hard to come up with a setting that would let him get away with it. The biological difficulties are frequently lampshaded, and provide a fair amount of the comedy in the series.
- Planetary Romance: The Viagens Interplanetarias series is an attempt to do a semi-Hard SF version of the genre.
- Tyop on the Cover: One edition of Rogue Queen had errors in both the title and the author's name, becoming Rouge Queen by L. Spraque de Camp.