H. S. M. Bradbury and Brian Bracegirdle
Introduction to Light Microscopy.  Garland Science, Taylor and Francis, Florence, Kentucky (2nd Edition). 136 pages (1998).

"Objects of interest to us exits in a very wide range of sizes but the unaided human eye is unable to see the smaller ones because its performance is limited. We rely very much on vision for the largest part of our information about the world about us, and the ability to see small things has come to play a large part in science and technology with consequences for daily life. Many documents are still stored in the form of microfiches which need magnification to allow them to be read. Microscopes are of value in fighting disease, for it happens that many parasites are small and many cellular components are smaller still, and to see both is to begin to understand both better. This simple statement conceals a vast amount of current scientific enterprise throughout the world, generally in specialist laboratories, and the accumulation of details of the most intimate workings of the bodies of all living things. Again, much surgery is now carried out with such precision that microscopes are needed in its execution."