I'd recommend "Journey through genius" by William Dunham. There's a bunch of great stuff in there including two chapters about Georg Cantor and his explorations

I'd recommend "Journey through genius" by William Dunham. There's a bunch of great stuff in there including two chapters about Georg Cantor and his explorations of infinity, including how he showed there is no 1:1 correspondence between integers and real numbers, while there is one between integers and rationals.