Art History is the systematic study of artistic production through the ages. It is sometimes taught as a long slideshow with historical commentary leading up to an exam, but that is not the main point of it. Instead Art History is a way of understanding history, culture, and ourselves as well as a fascinating way of getting to know people from times gone by; by understanding where they saw beauty (or whatever they saw). Contemporary Art History deals with a lot of non-art related visual stuff as well; advertising, design, comics, architecture, pornography etc — in order to better understand our own society.
Art History as we think of it today is a young academic subject, dating from ca 1900 when education in aesthetics was broken up into several subcategories, among them musicology and Art History.
The first historic work on Art that is known is by Pliny the Elder who wrote about it among many other subjects. The first book that more systematically tries to formulate a history of the art is most likely the renaissance Italian Giorgio Vasari’s "Lives of the Most Excellent Architects, Painters and Sculptors" written in l550, that gives us information on artists and their work, some existing some mythological.
Art history as it is done today, with less emphasis on biography and the moral example of the great work of Art and more on understanding and context of artworks, develops gradually during the nineteenth century, mainly in Germany, with Winckelmann as the leading writer. Late nineteenth century was also the time when most of our large museums and collections were established — they too are part of forming the development of Art History. The nazification of Germany during the 1930’s forced many of the most brilliant art historians such as Gombrich and Panofsky (as well as other scientists and artists) to flee Germany, either to Great Britain or to the USA, and so the bring with them their way of doing Art History.
Contemporary Art History, as well as history of Contemporary Art, tends to focus on the field of Visual Culture, to study many various forms of visual communication, often with examples from both Art and less highbrow visual phenomena. Art is then seen as a special case of general visual communication. "Reading" the visual is not an easily grasped idea, we can all read books because they are written in a language we understand. Images are not written in a general language but in a very special and personal style, and need to be "read" as such. Art History knows of many techniques for doing this, among them theory of art, history of art, semiotics, psychology of perception and art sociology.
Some art historians (like myself) are more preoccupied with the ever growing uses of visual devices in society and what this may tell us about the functions of this society as compared to other societies with other ways of handling the field of the visual. The most excited Art Historians talk of a paradigm shift, from Literature as the dominating cultural discourse ("the linguistic turn" ca 1950) to an "pictorial turn" that begun ca 1980 — when the debate of the post-modern project started.
For me personally Art History has become a way of understanding bits and pieces of a very large world that includes many layers of history, as well as many ways of interpreting and retelling this history. I do enjoy looking at objects and to be able to decode them and tell when, how and why they where made (or at least be able to know how to read up on that particular object), but the greatest benefit for me has been the inherent promise of some kind of understanding of whatever I see.
Slideshows are great, I use them myself when I teach, but they are far from enough, and they are not the main reason for Art History. If you still don’t see the virtues of it, get hold of a good guide at an art exhibition and take your time to really understand all the questions and issues surrounding the works you meet and you will, in time, develop an interest in the history of the visual. | 
