I've crawled the web and found solutions to most problems I've run into with drush and git - but:

sh: mysqldump: command not found

After executing, the drush sql-dump command does not appear to have a solution.

At any rate, your book emphasizes drush as a "best practice", refers readers here for initial install of git and drush - no updates provided, as would be expected. Thanks for any help in resolving these issues. My apologies if these issues are addressed in later chapter updates here on the site - but if so, a forwarding link would be helpful?

This is all very highly "technical" for those wishing to learn Drupal. I can note that best practices would involve using drush - but it is disheartening to be "hit" with all of this very early on, with no resolution to what I expect would be common issues encountered by those learning Drupal and attempting to follow your instructions.