It's been almost three years since I began spending nearly every available evening and weekend learning code and web dev. It's been a great adventure. However, contrary to the advice I was given I believe Ruby on Rails is not an effective place to start learning web dev, it certainly wasn't for me.
When I started, I had limited knowledge of HTML and almost no experience with CSS, Javascript, SQL or HTTP. I felt bombarded going through Michael Hartl's book (ruby.railstutorial.org), for example, trying to pick up all the concepts mentioned above plus the ideas of Unit Testing, ActiveRecord, the MVC paradigm, Rake, GIT, Migrations, layouts, partials and UNIX, to name a few. Nothing was sticking.
After now learning some programming fundamentals through an awesome Coursera course, learning C++ and Python to make small game mechanic, digging into PHP and launching a few fun websites, building a few projects with raw HTML and CSS while having lots of fun with jQuery and Javascript I feel I am ready for and can appreciate Rails. I'm now approximately 4-6 months from launching my first commercial product and this book will be perfect for my current purposes. I'm 25 pages in and can say that I love it's narrow focus (not including unit tests, for example) and also it's thorough explanation of all core concepts. I've backed the Kickstarter and can't to keep learning! Sorry for the long post HN! Long time lurker, big fan.