Professional Excel Development : The Definitive Guide to Developing Applications Using Microsoft Excel, VBA, and . NET by Rob Bovey, Dennis Wallentin, John Green and Stephen Bullen (2009, CD-ROM / Trade Paperback)
Really good book. Other books claim to be for professionals but are not more than just a bit beyond the basics. This book takes you really 10 steps further. Too bad it's a bit dated (anno 2017), and talks about Hungarian notation as the way to go, although they do say you have to choose the method that works best for you. Other than that absolutely the best book about excel vba I've ever read.