In a thread about Jeremy Silman's "The Amateur's Mind", a few members of chess.com sang the praises of Artur Yupusov's "Build, Boost, Evolve" series of chess books. Intrigued, I found a copy of the first book of the series "Build up your Chess: The Fundamentals" and started reading. I'm only on chapter 3, but this looks like it's going to be an excellent book and an excellent step forward for me.
The book is divided into themes (checkmates, the opening, etc.) with some game examples to give an insight into the theme, followed by 12 exercises. I'm really applying myself with the exercises. They're hard. The mates in the first chapter were not too hard to find, but in the second chapter, they got a lot harder. I'm now doing the opening exercises, and they are very complex. I've decided to add to this difficulty by setting the position on my board, but I don't move the pieces until I have found a line. (I move the pieces when I write down my solutions.)
I don't think I'll have finished this book any time soon, and it's only the first of nine! I'll continue doing the exercises, and I'll update you on my status.