The overview links to the book. See: https://ggplot2.tidyverse.org/
> ggplot2 is a system for declaratively creating graphics, based on The Grammar of Graphics.
> ggplot2 is a system for declaratively creating graphics, based on The Grammar of Graphics.
Springer runs occasional sales up to 40% discount about once a year, but a don't recall if "The Grammar of Graphics" was eligible last time.