I’ve wanted to get a better handle on the Dependency Injection for a while, and discover what the optimal approaches are.

Dependency Injection In .Net by Mark Seemann is a great book on the subject, with good examples and clear writing. When new concepts are introduced, the author includes concise definitions and copious references for further reading. I recommended it, and I was particularly pleased to see the epub version on the book available in addition to pdf and .mobi formats!