I am enjoying a book called Teaming with Microbes by Timber Press. It is an excellent argument for organic methods. A bit dense with scientific terms, but if you really want to get the whole picture I don't see how the authors could avoid talking in some detail.
It tells basics of soil composition, all the groups of critters in soil (bacteria, fungi, nematodes , minibeasts) . and what they do. Explains how they all interrelate and how plant roots work with them, beyond mycorhizzae... Well, you just have to read it, I can't do it justice (esp at this time of night 8^P)
Another very good book from Timber Press.
When I make soil from clay and compost and amendments, I can see a huge difference between "raw soil" and soil after it has had time to accumulate populations.
Now I tenjd to screen and amend raw clay, add compost and "innoculum" from healthy beds, then leave it in a heap for months before moving them to my beds.
I'm going to look for a used copy, becuase I was amazed by a chapter in a microbiology text that talked only about endomycorhyzzia (sp?) Some root hairs only do well if they have all four of the symbionts that they like.
And I firmly believe that healthy micro-flora and fauna crerate and sustain soil structure and wicking.