@noelrappin On page 89 of the PDF in the last sentence of the last paragraph of the page and just before the example that begins “class Child < Parent,” there is an out of place #{sec.super} which doesn’t appear to be part of the subject being discussed and is in a place where there would normally be a reference to another part of the book.

"...that were given to the original method.", more about this in #{sec.super}.)
^ <----                              ----> ^   outside ""? ----> ^^^^^^^^^^^^

Is it possible that string interpolation didn’t happen because one of the double quotes preceding #{sec.super} in your book’s source wasn’t escaped?

Also, as I was writing all that I noticed something else:

Should this punctuation:

"...that were given to the original method.", more about this in #{sec.super}.)
                                    ----> ^ ^ <----

be changed to this?

"...that were given to the original method," more about this in #{sec.super}.)

Or, maybe this is even more appropriate?

"...that were given to the original method"; more about this in #{sec.super}.)