When I was in Fourth Grade, I was introduced to the Hardy Boys. I read the Viking Symbol Mystery, and really enjoyed it being a Viking myself. Well, I eventually read all the Hardy Boy books in that original series. Later I learned the books had all been rewritten, so I hadn't actually read the "original" stories (except for one I found at my Grandpa's--at the time I couldn't figure out why it was completely different from the book of the same title I had read earlier).
There were so many things I loved about those books--great characters, exciting adventures, knowledge of things I'd never heard of before. But it was the artwork I was especially drawn to (pun intended). The covers each had a beautiful painting, and inside were several black and white pen drawings with a caption. Years later I would find a facsimile copy of The Adventures of Superman written by George Lowther with a painted cover, several black and white pen drawings, and four color plates by Joe Shuster. I loved that format. (Years later I found some reprints of old pulp novels--The Shadow and Doc Savage--that also had the painted covers and interior illustrations.) Again, I loved the format. This is the way a fiction book should be.
So when it came time to write my own book, that's the format I went with. Here is an illustration from that book done in the same style as the Hardy boys, The Adventures of Superman, and The Shadow.