After some online searches didn't tell me how much of the book concerned horse racing, I started typing a message to Scott to ask. Mid-message, I realised I could probably answer it myself.
A quick search for the book's title with search operator filetype:pdf located a copy. It's 377 pages. I could control + f for horse racing, but my dad likes other sports too, so I figured I'd come this far, let's take a second and do this properly.
Wikipedia had a lit of all sports but it's a tad too comprehensive for what I needed, so I grabbed a list of sports off another site that came up when I searched for a list of sports.
I wrote 30 lines of tidyverse code [1] that downloads the 377 page pdf, parses every word in it, filters on the list of sports, groups by word, and provides the number of occurrences of each sport in descending order: providing a rough indicator of how much of the book is dedicated to each sport, all in a few minutes of coding.
As someone who codes a lot in ruby, I have a high bar for 'developer happiness', but say without hesitation that R and its tidyverse are joy: expressive (almost always read left to right, top to bottom - just like the prose of a book), fast, reliable, succinct, and productive.
For anyone put off by R's indexing starting at 1 rather than 0, or by use of <- instead of = for assignment, I encourage you to suspend your hesitation for a short while to discover the tidyverse: you may well discover it to be a pure joy.
[1] https://i.imgur.com/E64yF4Y.png
[2] https://pastebin.com/Danc9KNr