I read a book around 1956 or 1957 - probably written in the late 40's or early 50's - and don't remember the title or author. The story was essentially about a young man going through a rite of passage that required him to visit outside societies which he must access by climbing a ladder to another level. As he progresses, he realizes there are 7 levels of societies that are in a concentric sphere and each level has a function to perform. He comes to realize that generations prior, all of the levels communicated with each other and that they are controlling their existence which is a giant spherical spaceship which was launched from their ancestral homeland, called "Urth" thousands of years before when it was doomed to become uninhabitable. Over time, the levels lost contact with each other but continued their ancient tradition of performing their specific role in providing for the other inhabitants of the spaceship. The young man brings the various groups together just in time to realize that they are about to crash into their destination planet which is to become the new homeland for their remnant of humankind. Does anyone know if this book still exists?
I believe the book is: "The Star Seekers" by Milton Lesser from 1953. It is part of the Winston Science Fiction Set Series of books.
A brief excerpt is below:
All Mikal knew when he embarked on the "Journey of the Four Circles" was that every eighteen-year-old from Astrosphere, the outermost circle, must visit each of the other circles if he hoped to become an Enginer. But before he completed his trip, he unearthed startling truths that threw the four circles into a state of chaos. Gradually Mikal discovered that unless the people of the four circles took immediate action the ship was doomed to crash. Mikal's desperate efforts to unite the four circles in order to save their world is a story of rising tension and clashing interests.