Skylark is a science fiction/space opera series by the late E. E. "Doc" Smith. The first book The Skylark of Space (first published in Amazing Stories in 1928) is revolutionary in the genre, in which a scientist discovers a space-drive, builds a ship, and flies off with a female companion to encounter alien civilizations and fight a larger-than-life villain.
The science in the "Skylark" series is more accurate than in, for example, Flash Gordon. Newton's laws are obeyed, planets circle suns instead of wandering through space, there is a description of something like a black hole or neutron star, and matter-energy conversion is involved in the space drive. As is usual in space opera even today, time dilation is ignored or swept under the rug with a bit of pseudo-scientific gobbledygook. There is also an interesting prediction of a nuclear weapon, describing the effects as "searing, killing, unbearable radiance" and creating a "tremendous mushroom-shaped cloud which was hurling itself upward at an appalling pace and spreading itself outward almost as fast."
The Skylark of Space was the first of a series which continued through 4 books -- Skylark Three and Skylark of Valeron written during the 1930s, and Skylark DuQuesne, written much later in 1963. The entire series describes the conflicts between the Seaton and Crane partnership, and DuQuesne and his minions, which often break into open warfare. It also includes depictions of progressively increasing scales of conflict between themselves, individually and collectively, and a series of non-human aliens bent on universal conquest. Eventually, being forced to cooperate against an alien species which had conquered one galaxy and was expanding into others, they concluded that the universe was large enough to allow themselves to exist together in peace.
Allies -- The peoples of the nation of Kondal on the planet Osnome, and particular Crown Prince Dunark.
Enemies -- Dr. DuQuesne; the first of the "disembodied intelligences"; the peoples of the nation of Mardonale on the planet Osnome.
Technology -- The discovery of a mysterious "platinum group" element, designated "metal X", which catalyzes the total conversion of matter to energy under the proper stimuli (specified to include an electric current with simultaneous activation by the radiation field produced by an early particle accelerator); the further discovery that such activated metal can generate a field which is capable of accelerating a ship to faster than light velocities at accelerations (relative to the external universe) on the order of "c", inferred to mean 300,000,000 m/s/s or 30 million g's, but with forces inside the ship of no more than 10 - 20 g; and that such activated metal can be directed to focus on a single specific mass (such as the earth) for location and direction. (The power used for maximum acceleration can be estimated from the total conversion of 400 lb of copper in 48 hours using E=mc^2 as 95 kilotons/second. With an estimated weight of 4,000 tons, the conventional newtonian acceleration may be estimated as 361 g's, which is clearly not compatible with contemporary physics.) The gift (from the Osnomians) of the process for converting regular metal into the super-strong, transparent arenak. "Attractor" and "Repellor" beams, which may be the first literary appearance of the concept of a Tractor beam]
Weapons -- Radiation-free nuclear explosives packagable as handgun bullets based on "metal X." Various beam and plasma weapons developed from Osnomian technology.
Allies -- The dolphin-like intelligent species of Dasor, and the advanced but pacifist scientists of the planet Norlamin, all part of the same multi-sun solar system of Osnome.
Enemies -- Dr. DuQuesne, who is seeking to duplicate the capabilities of the Skylark; the Fenachrone, a humanoid species bent on the conquest of the galaxy and the destruction of all other life forms.
Technology and Weapons -- The "zone of force," a stasis field in the ether; advanced propulsion and weapons technology stolen from the Fenachrone; the refinement of these technologies using the total conversion power capabilities of "metal X" into a comprehensive, massively integrated "fifth order" weapons, power, and communication projector operating at the "first order below the ether" and capable of faster-than-light but still limited propagation speed. At the end of the novel, the massive ship Skylark Three has 20 times the acceleration potential of the original Skylark, and the factor which limited the impact of the acceleration on the crew has been refined so that the interior of the ship is effectively weightless.
Allies -- The human peoples of Valeron, a planet of a highly distant galaxy.
Enemies -- Dr. DuQuesne, who has succeeded through subterfuge in duplicating not only the capabilities of the Skylark but also of Skylark Three; the surviving Fenachrone; the full colony of "disembodied intelligences"; the inhabitants of a "fourth dimension" that Seaton and crew pass through to escape the intelligences; the chlorine-breathing, amorphous Chlorans who are attempting to conquer Valeron.
Technology and Weapons -- Armed with the combined knowledge of the chief physicist and the chief psychologist of Norlamin, Seaton deduces that intelligent thought is a manifestation of "sixth order" forces, faster and potentially more powerful than the fifth-order forces powering the Skylark Three. By the end of the novel, he has refined this into the artificial "Brain" at the center of his 1000-km diameter spaceship, the Skylark of Valeron. The "Brain" is capable of simultaneous thought, computation, and control of all forces from ordinary electromagnetism through gravity up to thought and the other explored bands of the sixth order, and its abilities include the manufacture of the Skylark of Valeron to specification, directly by conversion of ambient energy into matter, in a period of six hours. Valeron includes artificial gravity, the ability to travel intergalactic distances on the order of few months using accelerations of more than 5 times that of Skylark Three (the only benchmark value cited, the intergalactic travel capability noted requires systems with acceleration capability another 500 - 1000 x greater than that; however, it should be noted that this was the acceleration relatively near the end of the Valeron's journey and that the ship may have run significantly faster in the part of the trip that was glossed over); a complete map of the entire universe stored in viewable three-dimensional form, and the necessary controls to direct communications and flight on multi-billion light year scales. Finally, the technology allows Seaton to capture and imprison the intelligences.
Allies -- The human species of the Llurd empire and the Chloran galaxy. DuQuesne and the remaining Fenachrone, who are also threatened by the Chlorans.
Enemies -- DuQuesne, who still attempts to murder Seaton and company prior to their alliance; the logic-driven, monstrous Llurd; the Chlorans.
Technology and Weapons -- Both Seaton and DuQuense build or upgrade to even larger and more powerful spacecraft than the Skylark of Valeron. One of the Llurd humans develops a technology making possible instantaneous matter transference over intergalactic distances. Seaton develops a defense against using the transference device as well. Both involve fourth-dimensional shortcuts. The transference device is scaled up to battle the Chlorans at the end of the novel. The Llurd situation is settled peacefully.