Saying what book you're talking about is kind of a spoiler now for anyone that happens to be reading its series. Are there spoiler tags on HN? <SPOILER> The Long Utopia, book 4/5 of the Long Earth series by Pratchett and Baxter. </SPOILER> The series has very meh characters/dialogue, excellent ideas and sense of nearly possibility-unlimited discovery that's executed very well, highly recommend if that's your cup of tea. Ended up skipping all the flashback chapters near the end of the series though, that felt like a load of filler