The Cosmic Courtship, written by Julian Hawthorne (the son of Nathaniel, of The Scarlet Letter fame) was serialized in pulp magazines in 1917, and hadn’t seen print since then until Cirsova Publishing came along and offered it in novel format. It’s considered an early science fiction work, though like all good science fiction it was a story not centered around gadgets and theories but instead some of the more abstract motivators of human activity: love, redemption, and self-sacrifice.
The science is more fantastical than technical; this, probably, is a product of the times in which Hawthorne grew up. The electric era was well underway, Einstein and general relativity were in the spotlight, so the bright promise of what the material sciences could accomplish in the future, as well as all of the attention now being paid to cosmic-level forces, were flashing about in everyone’s heads. It makes sense that contemporaneous writers’ imaginations would run with it without need for the believable explanations for the future tech.
The romantic aspect feels overwrought to modern reader sensibilities, but keep in mind this is the pulp era: exaggeration was a prime storytelling vehicle. Spirituality was presumed as part of the characters’ identities, and mentions of God or the supernatural realm slipped out naturally in dialog, when characters offered advice or consolation. There weren’t tired theological arguments or gotcha one-liners. Nothing terribly scary (it’s not The Cosmic Consternation) nor gory, except for a few small descriptions that come about from action scenes.
The book is noticeably archaic, but it’s likely a more enjoyable read if you’re as worn out as I am by all of the violence and prurience of modern science fiction.