I apologize if this is not the correct place to ask this question.

I am currently taking an intermediate photography course at my local college this semester. The problem is, I'm having the same problem I had in the basic course: I don't understand how to manually use aperture and shutter speed, for instance. I don't understand the numbers and their relationshp and the results. My shots turn out quite well and when I had taken the basics course, my written tests were low because I didn't understand those numbers and relationships. Yet I had the highest marks for my assignments (the photos themselves). So, I'm thinking I need a real good book that I can use more like a textbook ... something that spells out, "if you want this effect, try/do this" "when you do this, this happens". In other words something that both visually and in very simple terms explains the mechanics.

Any recommendations would be greatly appreciated.

THank you,

Diane