Book 67 is All These Worlds, which is book 3 of the Bobiverse series by Dennis E. Taylor.
Rarely have I liked a trilogy this much. There were tough moments but all in all, this was an original and wonderful idea.
The only other time I have seen this idea of alternate selves was in ultimate dimensions. Taylor solves this with one dimension and the idea of slight differences in instantiations of the same person.
You know Bob 0 is no longer around.
A brilliant series worth reading, despite the slow middle bit.
4 Bobs out of 5.
Should I read this? For all modern sci-fi fans.
What did I learn? White middle-class male entitlement may persist hundreds of years into the future but at least I'll be dead.