Footnotes, Endnotes, and Other Publishing Gaffes
Time to pick some reference-related nits.

There's nothing inherently wrong with opting to forgo legacy publishers. I've done it six timesāand I'm hardly an anomaly.
Eschewing the publishing establishment is both liberating and a smidge daunting. You can create the book exactly as you wish. There are so many things to know and do. In this post, I'll describe a subtle yet important element of book design that separates non-fiction pros from poseurs.
Footnotes
Footnotes ought to reference optional facts that just don't make sense to include in the main text. Here's a perfect example from the fourth Racket title, Reimagining Payments:

In this case, the derivation of custodian isn't essential to know. What's more, you or your designer should place them at the bottom of each referenced pageāand not the following printed one. Doing so allows the curious reader to delve deeper. In a properly formatted ebook, each footnote is a clickable link.