Disclaimer - I was the independent technical editor for this book. Nevertheless, I didn't have to write a positive review, or indeed any review at all, so I hope that this endorsement should be all the more valid. I am not a Wrox employee.
I own many books on Ruby on Rails development, and Ruby on Rails for Microsoft Developers has to rank as probably the clearest and easiest to follow exposition of technology and technique of all of them. The book takes a set of logical progressive steps through Rails development, stopping along the way for the occasional very deep dive into the internals. Chapter 7, on ORM with ActiveRecord, is a case in point, and an excellent detail piece for those who want to understand data modelling and database management within Rails. Like many developer books, this one has a theme of a developing application - a blog management system - and the development process is used effectively as a way of bringing in many of the modern essentials for the Rails developer. Topics covered include incremental development, adding textile support, handling of published versus non-published articles, pagination, comments, creating RSS feeds and of course selective use of AJAX techniques. There is also, unusually in my experience of Rails books, good solid coverage of deployment of an application into production with all of the consequences you can expect.
Given the title it would have been remiss of the author to have not spent time on orienting current ASP.NET developers with Rails concepts, and indeed throughout the book there are comparisons between the mechanisms of ASP.NET and Rails for carrying out many of the common development processes for web applications. However this is no Microsoft-basher's bible. Look in vain for the striking of religious poses - Antonio keeps to the point and sets out the facts.
So if you are a current ASP.NET developer or even just a Windows developer who wants to try out the Rails way of development, I can heartily recommend this book.