Eminent British scientist and writer John Burdon Sanderson Haldane wrote that "the universe is not only queerer than we suppose, but queerer than we can suppose." Astronomer Frank Tipler argued that there must not be any intelligent life in the universe besides our own species, because any such species would develop star-faring self-reproducing robots to colonize the universe, and that they would have run across our planet by now; Carl Sagan suggested that this view represented a failure of imagination, and that surely any species capable of such an audacious plan would have more interesting tasks to accomplish.
The first two books of Kevin J. Anderson's Saga of Seven Suns series posit a world where even the aliens fit into categories already thousands of years old, less strange than we can or have already imagined. Humans and the easily-recognizable aliens have no task more lofty than to spread throughout the universe as rapidly as possible; the less-human aliens have nothing better to do than to try and stop this expansion.
"Hidden Empire" (volume one of the series, now out in paperback) sets the scene and starts the plot in motion: by turning a large planet into a small star, humanity accidentally ignites a war with the heretofore unknown inhabitants of this planet and other gas giants spread throughout the universe. The aliens attack, and neither mankind nor the seemingly-benevolent Ildiran empire can stop them. Death and destruction follow, especially as the hydrogues clamp down on the fuel required for interstellar flight.
Book One ends with a cliffhanger, with an archaeologist's life under threat. But "A Forest of Stars" (volume two of the series) inexplicably picks up five years later, and leaves us dangling for more than one hundred fifty pages. Well, almost: dramatic irony is employed to such an extent that even a modestly attentive reader can get several hundred pages ahead of the action. Any suspense in the first two hundred pages of the series can be avoided merely by reading the hysterically overblown blurb on the back of "Hidden Empire."
For readers who devour plot, "The Saga of Seven Suns" is acceptable space opera: political machinations within the three branches of humanity and within the Ildiran empire take up the bulk of the books. This action is rendered plausible and the characters, while just the barest wisps of humanity clinging tenuously to bare archetypes, are just hearty enough to carry the reader along. Anderson's chapters are each told in the third person, looking over the shoulder of one of the numerous characters who populate his universe, though occasionally he shifts perspective within a single chapter. This violation would be far less jarring were the chapters not all titled with the name of the character whose perspective is applied.
In addition to this series, Kevin Anderson has co-written books set in both the "Star Wars" and "Dune" universes, and those influences shine through: The three branches of human society are the mainstream / corporate branch (the Terran Hanseatic League); the spacefaring Roamers, who may be adequately imagined as a society composed entirely of Han Solo and MacGyver stand-ins; and the Therans, whose telepathic priests are completely hairless and green-skinned, who look and act as though they channeled Yoda and not the trees of their World-Forest.
Anderson clearly likes elemental divisions: of the vastly ancient previously unsuspected alien races, by the end of volume two there are four-and they are associated with air, earth, fire, and water. While three of the four are on the side of humanity, at least three more volumes are planned, and the groundwork has been laid for betrayals by at least one of the three.
In addition to the human-like Ildirans and the four elemental aliens, the only other recognizable aliens so far are the long-extinct insectoid Klikiss race, and the still-functioning robots that they created, and who now wander the spiral arm with their own hidden agenda.
Fans of fantasy novels, "Star Wars," and the like may find "Hidden Empire" and "A Forest of Stars" to be enjoyable: the settings are opulent, the pageantry is bold, and the military action is extensive. However, readers interested in carefully-imagined political or social structures would be well-advised to look elsewhere. As would readers who demand some sort of fidelity from the science: I laid out the initial scenario to half a dozen friends, and every single one located the same crucial flaw in the premise. But this is space opera, meant to be rapidly devoured and passed through nearly undigested. If such books are to your taste, the thousand-plus pages to date of "The Saga of Seven Suns" are a tasty treat indeed.