Hi. I'm a junior math and physics major. I'm hoping to go to grad school for a Ph.D. in math, and I'm trying to figure out some good schools to apply to. I found the math subject I enjoyed the most was functional analysis. I did a basic course in it using a book called Introductory Functional Analysis by Kreyszig and it was one of the most enjoyable math books I've ever read and the problems were pretty fun. However, I'm not too sure exactly what schools I should be looking at for grad school. Does anyone have any suggestions of schools that have a good group of people specializing in functional analysis or operator theory? Also, if anyone has any recommendations for books a bit more in depth in the subject, that would be cool. Thanks!