Ansel Adams is an amazing black and white photographer. He focuses in large scale landscapes, but has truely paved the path for modern photography. Instead of simply going out places and taking pictures, he would visit an area and take measurements and watch the surroundings to gather the information needed for the perfect picture. In black and white photography you can tell a well structured picture by noticing if it has an equal balance of white, black, and grey. This is incredibly hard to do without knowing precisely how to adjust your aperture and shutter speed. If you have never seen any of his work, you should check it out.