A trilogy of novels co-written by Creator/RykESpoor and Creator/EricFlint: ''Boundary'', ''Threshold'', and ''Portal''. A discovery of an aeons-old alien base on Phobos with connections to a mysterious fossil sends paleontologist Helen Sutter and a crew of associates on a mission of exploration through the Solar system, first to Mars and Phobos, then to Ceres, Jupiter, and beyond.

!!Tropes in the Boundary series:

* TwentyMinutesIntoTheFuture: The book is set at an unspecified point in the future with somewhat more advanced technology, mention of an attempted coup against the government in the past (by a cult leader who Madeline's AbusiveParents were followers of) and the Patriot act having been repealed twenty years earlier.
* BadassBureaucrat: Director Andy Hughes is a BenevolentBoss whose good at putting his foot down at the stupidity of his boss and carefully but firmly explaining why a certain path of thought (generally beneficial to the heroes) should be followed.
* BaitAndSwitchTyrant: Dr. Glendale is introduced seemingly offering support to a man accusing Helen of academic fraud, helping him build up a hypothetical case. Then he yanks the rug out from under the guy by describing the millions of dollars such a hoax would cost, making it clear that Helen couldn't have faked it, before serving as a major ally afterwards.
* CanisLatinicus: Finding a mysterious fossil of a never-before-seen organism, Helen Sutter names it ''Bemmius Secordi''. The ''Secordi'' is for the Secord family, on whose land it was found. Only a few people catch on that the ''Bemmius'' is her covert reference to "Bug Eyed Monster", as she's convinced it's the fossil of an alien but which isn't something she dares state publicly.
* CoolStarship: The ''Nebula Storm''.
* {{Cult}}: Madeline's parents were members of one.
* DesignatedVictim: ''Boundary'' incorporates the Creator/BaenBooks house joke of killing off Joe Buckley. In this book, [[spoiler:it's subverted -- despite teasing his impending doom from the very first sentence, and on multiple occasions since, he survives. He not only survives, he gets rich through his excellent, designed for space 'Joe dinners' and ends up married to Madeline Fathom, arguably one of the most beautiful women in the solar system.]].
* DrivenToSuicide: [[spoiler:Richard Fitzgerald]] in ''Threshold'', after being ejected into space with no hope of rescue.
* DwindlingParty: The European crew in the second and third books, less than ten of whom survive some DisasterDominoes.
* EverythingSensor: The Fairy Dust is a relatively realistic version.
* GenreSavvy: Madeline is quick the practical reasons why covering up the discovery of the alien base won't work and how the government isn't going to try to do it.
* HeIsNotMyBoyfriend: A.J. and Jackie are two scientists who work together and are friends; they also bicker a lot. As such, Jackie always gets ribbed by the other people in their team about her "boyfriend" A.J. She vehemently denies these accusations to the knowing reaction of the others. [[spoiler:Ultimately subverted, as A.J. ends up with Helen, and Jackie smugly declares to everyone within hearing distance, "I ''told'' you he wasn't my boyfriend."]]
* IdiosyncraticEpisodeNaming: OneWordTitle ThemeNaming about thresholds or something: ''Boundary'', ''Threshold'', and ''Portal''.
* JumpedAtTheCall: Madeline is happy to volunteer to go into space.
* LoadBearingHero: A cave-in in an ancient ice tunnel. Luckily, [[spoiler:Madeline's spacesuit could become rigid on command, so the problem was merely replacing her with other bracing.]]
* {{Nanomachines}}: "Fairy Dust". Also once used by the Bemmies for their slate displays and dusty plasma drive.
* OneWordTitle: As part of the IdiosyncraticEpisodeNaming ThemeNaming about thresholds or something:
** ''Boundary''
** ''Threshold''
** ''Portal''
* PhlebotinumKilledTheDinosaurs: It appears the asteroid which killed the dinosaurs was a weapon launched by the Bemmies.
* RedShirt: [[spoiler:Dr. Ryu Sakai, the least characterized of those who go down to Mars, and the only one to die.]]
* ShoutOut: to ''Manga/FullmetalAlchemist'', ''Manga/SaintSeiya'', and ''Anime/ElfPrincessRane/Fairy Princess Rēn'', for starters.
* TheSociopath: Richard Fitzgerald has no empathy for anyone and seems somewhat amused by chaos and cruelty.
* ThemeNaming: With the OneWordTitle IdiosyncraticEpisodeNaming about thresholds or something: ''Boundary'', ''Threshold'', and ''Portal''.
* ThisIsGonnaSuck: After a new energy source is discovered on Mars, Hughes tells the President's toadying National Security Advisor Jepsen that very soon they'll certainly be getting calls from the oil, aerospace, railed and auto companies badgering the president [[SarcasmMode "To know what he intendeds to do about that dire threat to national security."]]
--> ''He Managed to say it without a trace of sarcasm. A waste of effort, really, since by the time he was finished, the National Security Advisor was already out the door.''
----