Inverted World

This was probably a good book by 70s standards; it's still not a bad scifi and I did read it to the end (and the Grand Idea is captivating, though it had been redone several times since then); but for the modern reader, 50 years later, it also feels terribly slow, too straightforward and too dragged on - it was honestly a slug and I kept at it only for the explanation, which came too abruptly and too “told not shown”