Is it ok to use a outdated book to learn Rails?

Personally, no, I don't think it is advisable or necessary. There have been some dramatic changes between Rails 2 and 3, and now Rails 4 has arrived with even further changes. The book will also use Ruby 1.8 no doubt, but there are equally dramatic changes between Ruby 1.8 and 1.9, and now we have Ruby 2.0. As somebody who is just setting out to learn Ruby/Rails and how to take advantage of the whole ecosystem, I'd start with Ruby 1.9 and Rails 3. Many applications will use Ruby 1.9 and Rails 3 for a while. once you're comfortable, you could move onto Ruby 2.0 and Rails 4. I'd consider Ruby 1.8 and Rails 2 legacy, based on outdated techniques and technology. It is like starting with a stick and a stone instead of a hammer. One thing I really do wish I'd done from the start is read the documentation for Ruby and Rails, *then* read books about the subject: http://ruby-doc.org/ http://guides.rubyonrails.org/ Book: http://ruby.railstutorial.org/ Don't forget the wealth of resources available in the form of online courses. For example, this: http://railsforzombies.org/. Plenty of great information out there, just be sure to not overlook the documentation. Having a firm grip on the documentation is how you become an expert.

I would go a step further and suggest that Rails changes so quickly that it's almost impossible to recommend any book as being up-to-date with the most recent changes. This isn't like buying a used car; many best practices from Rails 2.3 have been deprecated in 3 and removed in Rails 4. You already have a learning curve to cope with without constantly wondering if the error you're trying to fix is the result of developer error or bad information. In the same vein, I really wish that people who write (often excellent) tech tutorial blog articles would stamp them with the version that was current at the time it was published. Turning Google and Stack Overflow upside-down for outdated information is the same problem in a different form. My actual best advice is to follow the RailsApps tutorials and recruit a great mentor as well as some friendly devs that won't mind answering the occasional question. http://railsapps.github.io/

A little outdated is almost inevitable. But Rails 2.0 came out over five years ago, Rails 3 was a major update, and Rails 4 is just around the corner (Update: out!). As says, there are a lot of resources out there, but I'd say for a "learn Rails" book, go straight to http://ruby.railstutorial.org/. (The online version is free.) The Ruby on Rails Tutorial is for Rails 3.2, so when you're done, check RailsCasts http://railscasts.com/episodes/400-what-s-new-in-rails-4 for the latest changes. (Update: The tutorial now has a supplementary chapter on Rails 4.)

There are still a lot of Rails 2.3 and 3.2 apps out there. I wouldn't use a 2.0 book to learn Rails but knowing the differences between 2.3, 3.2 and 4.0 would be useful especially if you're a consultant.

the internet is full of really good tutorials. Use them :P It is ok to learn how to build a cart or a normal car?[rhetoric]