what exactly is a historiography

Historiography is the history of history. So what you're doing, in essence, is talking about how historians talk about history. (Sometimes I've found that undergraduates decide that "historiography" is just a more fancy-sounding work for history. It isn't, and misusing it doesn't make you seem smarter. And despite what Microsoft Word's spellchecker says, historiography is a word...)

A practical example. Let's say I'm interested writing a history of the atomic bomb. A straight history of the atomic bomb would be about the scientists who built it, the political decisions that went into its production and use, the consequences and so on. Pretty straightforward. My primary sources are going to be things like interviews with people involved, government documents from the time, and maybe press coverage afterwards to talk about how the news was received.

Let's say I was writing a historiography of the atomic bomb. Now I'm writing about historians and my primary sources are historical works. So I'm going to talk about how Herbert Feis, a foreign relations historian, wrote his book Japan Subdued in 1966, and how his take on the history of bomb different from that of Robert Jungk, whose Brighter than a Thousand Suns came out in 1958. I'm going to talk about how Gar Alperovitz's Atomic Diplomacy (1965) put forward the thesis that the atomic bombs were just meant to scare the Soviet Union, whereas Tsuyoshi Hasegawa's Racing the Enemy (2005) argued that it was the Soviet invasion, not the atomic bombs, that led to Japan's defeat. I might talk about how Richard Rhodes' The Making of the Atomic Bomb (1986) relies upon "genius" narratives for telling its stories of the scientists, but nonetheless is ambiguous about the morality of the bombing. I could mention that Ruth Howes' Their Day in the Sun (1999) is the only book that really takes into account female contributions to the bomb project (which were substantial), but that it has been more or less ignored by most subsequent histories of the bomb written by males (hmm). I might even blur the lines between history and historiography by talking about how the original historical actors — like General Groves or Secretary of War Stimson — were very deliberate with regards to manipulating what was known about the atomic bomb, and in the process ended up writing the "first draft" of the history of the bomb (and many of their key arguments continue to be points of discussion by modern historians). Ultimately it can be quite wide, but what I'm looking at is how we talk about the history in question has changed over time — history itself becomes historicized.

So you can sort of see the difference here in my examples. What's the value of historiography, you might be asking? For one thing, it helps us see, at a glance, what different types of arguments and interpretations have been put forward. It can help us see the production of history as a product of its time, as well. It helps us be more critical about works of history, because we see that they themselves are products of their time and context — they don't sit "above" anything like that.

Here's something I wrote a few months ago in response to a graduate student looking for guidance in putting together a historiography paper:

It sometimes seems as though there must be only one way to write a historiography paper -- as if anyone can just describe the entire state of a field somehow -- but there are actually several ways to do this well. Also, not everyone's reading of the shape of a field or its most pressing issues will match up. Historiography papers will all be slightly different, in other words.

Depending on what issue you're addressing, one of several approaches may be most appropriate. Sometimes you may want to describe the field as a puzzle that's been pieced together over time. Every text is a contribution that makes the picture clearer.

Sometimes, a chronological approach is best. So, for example, scholars of Reconstruction in the 1920s put forward a compelling, field-defining theory to explain Reconstruction that was also extremely racist. That framework was poked at and partially deconstructed over the following decades, but wasn't really displaced until Eric Foner's Reconstruction in 1988. Scholars of Reconstruction afterwards branched off into many different directions, feeling less constrained to continue arguing against the scholarship of seven decades earlier.

There may be factions that have debated a particular key issue over time, and you may way to track the shape of that debate and the way it's impacted the scholarship produced over a certain period of time. A thematic approach can work, but only if the paper remains focused. No one wants to read a historiography paper that identifies 10 themes, three of which drop out as 15 more are added -- after which 5 more drop out again.

The important thing is that your historiography paper have an argument. It's not enough simply to describe the state of a field or how it got to be the way it is. What does it mean? What are the key issues or critiques that historians need to focus on? And in what direction should future research go?

The information you need to put this sort of paper together virtually always comes in the introduction and conclusion to a historical monograph. If you're in a history graduate program, you must know this already -- but that really is the place where the big ideas of the text are laid out, and it's those big ideas that you'll set in relation to one another in your historiography paper. It's especially useful when the literature review in those monographs gives you a sense of the state of the field that author saw at the time he/she published. State of the field essays are published from time to time as well, and those can also be helpful.

Oh, and one more thing. These papers can be a pain, but they can help you figure out where you own work fits within the larger field -- and that's a question that everyone has to answer. Hope that helps.

In addition to the answers already provided, I want to add that a historiography can also address gaps in research. Or rather, provide an analysis of where the research has been and how your analysis will provide a different approach. In this regard, chronological is often a good approach, but so is categorical.

Ultimately, what you're trying to do is provide your reader with a snapshot of the research so far and how you plan to expand upon or argue against that current line-of-thinking. In addition to giving you a focus, it demonstrates you have a masterful command of the topic so far. It's a good opportunity to convey to the reader that, quite simply, you know what you're talking about.

Source: MA in history; wrote a thesis

Most of the posted comments provide good information, but I'd suggest narrowing your subject matter to specific areas. Instead of writing a historiography of WWII, examine writings about the Battle of the Bulge; instead of the Cold War, write about the Cuban Missile Crisis or the Berlin Air Resupply missions. The tighter your paper's focus, the better it'll appear to a reader. Finally, always approach your readings by focusing on the differences between authors' approaches or methods. In many ways you're writing a series of book reviews on a single historical event. If you need help choosing the books to include in your historiography, begin with the most contemporary historian's writing on the subject and use his/her bibliography to identify the historical works they relied upon.