When I got into software development (from hardware) as a serious profession change, Clean Code was one of the first books I picked up. Originally, the content interested me from an agile and legacy code management perspective, but I found an amazing wealth in this tome of all things best practice.
This isn't one that's easy to just sit and read, but taking a chapter at a time, you'll find this is a worthwhile read--cover to cover.
Brownfield Application Development in .NET
I, like most developers, live in legacy code environments. About 10% of my work per year is totally greenfield, new development. Whether you're extending an existing architecture, turn and burning an old version, or just doing routine maintenance, the concepts in Baley and Belcham's book--especially around dependency injection, layering, and refactoring object-oriented structures--are really good.
As a side note, Belcham also has a related source on Pluralsight. I've never reviewed or taken it, but for those looking for the audio/visual experience in 2 hours--it might be a good bet!