Restoree (1967) by Anne McCaffrey is a science-fiction romance that's well worth overlooking in Anne's corpus. However, anyone interested in Pern would do well do read it, for in this unengaging work lies the seeds to Pern.
The plot revolves around Sara, who was kidnapped from Earth, only to come to her senses on an alien planet caring for a patient in a mental asylum. This man turns out to be the future man for Sara, more important to the future of this planet than she knows.
This book is a period romance. The heroine is firmly wedged into her mid-20th century socially appropriate roles as caregiver and woman. Early on she has the agency that she needs to propel the story along, but after a while, becomes bound by her genre's limitations. She can be an alpha social beast, but never the interplanetary hero.
As writing goes, the characters come across as bland. Some have their own agendas, but most of them are just sorta there. You don't really cheer anyone on, not build favorites. Objectively, the cast is entirely forgettable for there's no reason to remember any of them.
Where this novel connects with Pern is in its DNA. Our alpha male is the warlord of his planet, but he's been sidelined. Now he has to regain his command of the planet's fleets to stop an outer-space aliens species so bad that humans have taken to living in caves to escape them. There's an incompetent warlord in the way, of course. Although the planet has some high-tech to it, they're really a low-tech society that's using the alien's own tech to defend themselves. Other familiar features include the Warlord's half-brother, a looser definition of marriage, tunics (Anne always in this writing period), sailing, and council meetings.
Think of this as Pern 0.1. Think of this as Pern done wrong, but necessary in the evolution. It's there that Anne did everything wrong, but found a few things that she had done right, recycling them into those stories that became Dragonflight.
The novel is full of other period references as well. Tapes, screens, and circuits dot the book's vocabulary, emphasizing just how pedestrian Anne's view of the future worked. Not only is this a book brought out in 1967, it would have been written several years before, and if you include shopping the novel, several years before that, so a writing date of 1963 would be a fair guess.
In some ways, I found this novel entertaining despite its flaws. It isn't without merit. The book doesn't get bogged down by its own pacing, the romance moves along at an engaging clip, and there's some fun ideas at work. Being a slim volume, you should be done fairly quickly even with the pains it causes.