First of all, thank you so much @noelrappin for writing this book, I am just starting with Ruby and this book is very helpful.
I just wanted to report some typos I came across on several pages in the book. Here they are:

“the the” → “the”

• p 23: The username is not in any way connected to your Windows account—it’s a brand new account for the the Linux distribution you’ve installed using WSL.
• p 98: In this case, we’ve attached separate methods to each of the the two instances, so calling introduction on each instance behaves differently.
• p 117: The require call is at the the file level, and loads the module into the Ruby application as whole, the include call is at the class level, and adds the module’s behavior to the class in which it is included.
• p 229: We can run our tests at this point with the same command, and we’ll see the test fail because the the TennisScorer class doesn’t exist.
• p 255: You can find a list of the the tasks implemented by a Rakefile
• p 314: Here’s what the the Finder class looks like with Sorbet annotations added:
• p 455: For the three-dot form of a range, if the flip-flop is unset and expr1 is true, the flip-flop becomes set and the the flip-flop returns true.
• p 468: If the object prefixed by a block responds to to_proc, then to_proc is invoked and the resulting proc passed to the the method
• p 497: The sibling log methods log10 and log2 are also available and return the the log of the argument in the base of the method name.
• p 518: The method delete! does the same thing, but mutates the receiving string and returns the the mutated string.
• p 533: The block is then called with that 7 as the first argument and the the third element of the list—9—as the next argument.
• p 547: The greater then/less than behavior is based only on the relationship between the the two sets, not the values of the elements.

“covert” → “convert”

• p 491: The strptime method uses the format string to interpret the string and covert it to a Time.
• p 502: Any other type as the first value, and Ruby attempts to convert it to a string using to_str and parses that string (per the documentation, it does not appear that Ruby attempts to covert to a number).

Other

• p 104: In the previous example, we’d might want to make the helper methods private,
  because they shouldn’t be called from outside the InvoiceWriter class
  → I believe it should be either “would” or “might”

• p 109: Now that we have methods, we need to talk about how different classes can share functionality defined by there methods, it’s time to talk about inheritance and modules.
  → should read “their methods”

• p 114: The is a common idiom when using subclassing.
  → should read “This is”