Markdown is great for simple pages, but you need a Markdown pre-processor to do more advanced work like including another markdown file. E.g., you want to writ

Markdown is great for simple pages, but you need a Markdown pre-processor to do more advanced work like including another markdown file. E.g., you want to write a book and each file is a chapter. If you are writing something with code samples you might want the code files separate so you can test they are correct.