I am having a hard time finding this stuff on the net? What was the period and style of writing called that Shakespeare wrote in for example?
Shakespeare wrote in the Elizabethan period. He is also often identified as a Renaissance playwright. Part of your confusion probably stems from the fact that many periods and styles overlapped, and many are known under multiple names.
Romanticism was a movement during the eighteenth century(various sources will give the movement different dates). One of the fundamental ideas of Romanticism is the belief in the natural goodness of hummankind (the idea that humanity in a state of nature is superior to humanity in civilization). The works of Romantic poets often had mystical overtones, and regarded Nature as a source of physical beauty and a manifestation of greater spirit in the universe.
Realism was a literary movement that began during the nineteenth century and continuestoday. Realism essentially took the place of Romanticism. Realism focused on the actual rather the the imagined or fanciful as Romantic literature had. It was objective, and was, in many ways, inspired by the objectivity of scientific method.
Hope that is helpful.
Also…if you want a resource that offers definitions, I’d suggest looking for a University English anthology type of text. I have an old copy of “The Norton Anthology of English Literature” and, in addition to nice introductions to each time period in it, it also has a glossary of terms at the back with helpful explanations.
Naturalism (in the literary sense) is generally involved with bringing a scientific approach to issues (often social issues) explored in literature. Looking at a character and his or her actions as a result of that person’s environment might be a common theme, for example. There’s a bit of overlap with realism, as you might expect. Emile Zola (French novelist) is sort of the king of naturalism. Theodore Dreiser is a good example of an American writer. Generally, we’re looking at late 19th century here, and you can see the relationship between what was current in the world of science (and how it was presented in the popular media), and the themes that run through naturalist literature.