Okay, so I didn't read every paragraph of the 1,579 page tome that is .NET and COM: The Complete Interoperability Guide, by Adam Nathan, but what I read was great. Most of the book is full of useful information that helped me understand how .NET/COM interop works and how to most effectively use it. As for the rest of the book, well, I'll never have to go that deep (I hope), but I'm glad that it's there. Dox Box says it best on the cover of the book: “This is the last book that should be written about COM programming. There is nothing left to say.” Amen.

If you plan on doing anything but the most rudimentary P/Invoke and/or .NET/COM interop, you must own this book. It is both a comprehensive reference and a usable guide, and I highly recommend it. It's so good, in fact, that you might have trouble finding it; as of this writing, it is out of stock at Amazon and other online booksellers!