Updated: May 7, 2022
Renowned Harvard Astronomer Avi Loeb, in his book called Extraterrestrial, makes a convincing argument that Oumuamua came from another star system and proved itself to be a technological artifact--most likely a lightsail.
A new summary book from Scott Campbell and summaries1000.com shares the story in a more succinct format of 101 pages of ebook ($2.99) or 3 hours and 40 minutes of audiobook. ($3.99). Contains enough basic astronomy and astrophysics to rival a basic textbook.