The "Intermediate" section contains the canonical texts for undergraduate first and second courses in the "mainstream" mathematics subjects. The "advanced" section contains mostly intro and/or reference texts for research in each area (ie assume an undergraduate degree in Mathematics).
Some less main-stream areas (e.g. logic) aren't particularly well-represented.
https://www.ocf.berkeley.edu/~abhishek/chicmath.htm
The "Intermediate" section contains the canonical texts for undergraduate first and second courses in the "mainstream" mathematics subjects. The "advanced" section contains mostly intro and/or reference texts for research in each area (ie assume an undergraduate degree in Mathematics).
Some less main-stream areas (e.g. logic) aren't particularly well-represented.