Raising, Exception, Rescue

Although I took a week off, don't think I'm done with Ruby!  I'm continuing on the RubyMonk: Ascent book.  As of late I've been learning about exceptions, how to raise them, and begin - rescue - end.  These are easy to learn but difficult for me to put into a concept.  Thankfully, I've also been using the book Beginning Ruby by Peter Cooper.*  At first, the style of the book was a bit clutzy compared to Codecademy or RubyMonk, but I've really appreciated using it as a reference for times like these when the concepts seem a bit more abstract than what I am accustomed to.  What are your favorite references?

Photo Credit: RubyMonk: Ascent

*Cooper, P. (2009). Beginning Ruby: From novice to professional. New York: Apress.