1) RailsSpace by Hartl and The Rails Way by Fernandez are the best books out there right now. 2) Right time, right place. Rails came out around the same time

1) RailsSpace by Hartl and The Rails Way by Fernandez are the best books out there right now. 2) Right time, right place. Rails came out around the same time the second wave of web startups picked up. Also the argument is that Rails allows a smaller team (or even just one person) to write more functionality in less time. Whether that's true or not for you may vary.