Numbers opens with a census and repeats one in chapter 26, and the two lists have almost no names in common. That is not an accident of record keeping, it is the argument of the book made structurally. The generation counted at Sinai is not the generation counted on the plains of Moab. Everyone in the first list, with two named exceptions, dies in the wilderness in between.
The Hebrew name comes from the first verse, in the wilderness, and describes the book better than the English one does. The opening chapters arrange the camp: each tribe in its place around a sanctuary at the centre, the Levites in an inner ring, the order of march specified. It is a portrait of a people organised for a journey that is about to fail.
The failure is chapter 13. Scouts are sent into the land and ten of the twelve report that it cannot be taken. The people believe them, and the sentence is that they will have the wilderness they asked for, forty years of it, one for each day the scouts were gone. What follows is a sequence of revolts: Korah and his company challenge the priesthood and the ground opens; the people complain about the food; Moses strikes the rock at Meribah instead of speaking to it and is told he will not enter either.
The book is unusually honest about its own leadership. Aaron makes the calf in Exodus and is not removed. Miriam is struck for challenging Moses and Aaron, who made the same challenge, is not. Moses himself is barred from the land over an incident the text describes in four verses and does not fully explain.