Several answers here ignore the request in the question "I'm looking for a reference that explains different types of charts with respect to stats/math. I want more theory than process." In particular, books by Few, Knaflic and Yau are often weak (and even sometimes quite incorrect) in linking their discussion to statistical principles.

Antony Unwin's Graphical Data Analysis with R see publisher's site has much more on the logic of statistical graphics than many of the books mentioned in other answers. Its use of R as a vehicle need not be a disadvantage to people who mostly or wholly use some other software. I am one such person but I have found the discussion rich and challenging. Even I when disagree with the author on some details, it is worth working out why. This is a 2015 book: while I suspect that the R details may be a little out-of-date, otherwise this wears very well and bears repeated consultation and reflection.

Several answers here ignore the request in the question "I'm looking for a reference that explains different types of charts with respect to stats/math. I want more theory than process." In particular, books by Few, Knaflic and Yau are often weak (and even sometimes quite incorrect) in linking their discussion to statistical principles.

Antony Unwin's Graphical Data Analysis with R see publisher's site has much more on the logic of statistical graphics than many of the books mentioned in other answers. Its use of R as a vehicle need not be a disadvantage to people who mostly or wholly use some other software. I am one such person but I have found the discussion rich and challenging. Even I when disagree with the author on some details, it is worth working out why. This is a 2015 book: while I suspect that the R details may be a little out-of-date, otherwise it wears very well and bears repeated consultation and reflection.