A few years ago I participated in an online authors' panel sponsored by my former (now defunct) publisher. Accuracy in historical research was the topic of our discussion. Since that subject is always of interest to readers and writers of Historical Fiction, I'm posting an updated version here.

1. Period and Setting. Since my first novel, Confessions of the Creature, was inspired by Mary Shelley’s Frankenstein, the time (1799-1815) and the place (Russia & Europe during the Napoleonic period) were dictated by Mrs. Shelley’s work. You’ll probably begin with a good idea of the time and place in which to set your novel. But for more ideas, you might want to begin with a good comparative historical timeline. For example, my Oxford English Reference Dictionary has an excellent Chronology of World Events, containing a broad overview of cultural, political and technological developments from pre-historic times to the present.

2. Overview. Once you’ve set your time and place, get a good general history and take a look at relevant encyclopedia articles and biographical dictionaries. A familiarity with the literature of the period is helpful. For example, anyone writing Regency Romance ought to be familiar with Jane Austen. Underlining descriptive details—clothing, hairstyles, furnishings etc.—is a good starting point for drilling down in the next phase.
I began my research on “Confessions” by reading a good, contemporary paperback edition of Frankenstein that contained a concise biography of the author, a well-sourced introduction, an historical timeline (The World of Mary Shelley), extensive end-notes, and a list for further reading, including Mary Shelley’s other novels, Letters and Journals, Major influences on Frankenstein and Works about Frankenstein and Mary Shelley. That was a gold-mine of source material and a jumping-off point for Google searches on the internet. I also read collections of Percy Bysshe Shelley and Lord Byron (they appear as characters in Confessions, along with Mary) in paperback editions that also contained helpful source material for further research.
Next, since my protagonist Viktor, the transformed Frankenstein monster, was to become a hero of the Napoleonic Wars, I began with the military history of the period in a general overview and read a biography of Napoleon Bonaparte. I was also able to research on-line the memoirs of soldiers who fought in the wars and for more details of the Russian army of the period there was, of course, Tolstoy’s War and Peace. On-line research led me to a recently published history of the Russian Officer Corps of that period. With a wealth of information, I was ready for the next stage: organizing materials by category.

3. Details: In the final stage, it’s a good idea to organize your material by category and “missing pieces” can be filled in by on-line research. In my experience, the most reliable sites are those associated with institutions of higher learning and historical societies. And I kept a record of my sources for future reference. Here’s an example of categories for organizing your period research materials. The list is illustrative and by no means exhaustive, and categories can of course include sub-categories (see “Military” below), and some categories cross-over into others.

Fashions

Furnishings

Art & Architecture

Class Distinctions/Social Hierarchy

Political and Legal Organization

Military (Battle strategies, maps, uniforms, weapons, tactics, logistics, etc.)

Transportation and Communications

Technology

Economics

Philosophy and Religion

Medical Practice

Dining and Entertainment

Distinctive Customs/Manners and Morals

Pictures from the period (paintings, lithographs, etchings and, after 1840, photographs) are good for visualizing scenes, and there are plenty of visual references available in books and on-line. Movies and T.V. historical productions are also a good source, but a word of caution. The old classic Hollywood films often got things wrong. Fashions, furnishings, music, ball-room dances, etc. can be off by a decade or more. This brings me to the topic of anachronisms, and how I try to avoid them.

Years ago I read a biography written by a best-selling author and published by a major house. The era was Victorian, and I recall two glaring errors that ought to have been avoided. First, there was a reference to “wireless” communication in the 1870s. In fact, there was no “Wireless” until about twenty years later. The author should have used “wire,” “cable,” or “telegram.”
Second, there was a reference to “film” for a camera, again in the 1870s. At the time, cameras used plates; film wasn’t introduced until the following decade.
Now I’ll refer to two of the above categories: “Transportation and Communications” and “Technology.” If the author had done his homework (or, in the case of some best-selling authors, his researcher had done it) he could have referenced those categories when writing, and avoided the glaring anachronisms. And writers should not expect editors to catch that sort of thing.

Here’s an example from my own experience. In one of my published short stories, the protagonist travels from Paris to London; the time is 1848, just prior to the Revolution of that year. In my first draft I wrote that he took the Boat-Train from Calais to Dover, but I made a note to do further research because I wasn’t sure that that route had been completed at the time. My hunch was correct. In 1848, the French railway system had not yet been extended to the Channel Ports, and my character would have taken a coach to either Calais for the crossing to Dover, or Boulogne for a crossing to Folkestone. A minor detail that most readers might not have caught, but I’m glad I took a little extra time to get it right. Now if I’d been writing Steampunk, I might have had my character traveling through a Victorian era Chunnel!

A final word concerning info-dumps. After spending a great deal of time and effort gathering your material, there’s often an urge to show off your hard-earned knowledge by using everything you’ve got. I try to avoid that natural urge, and when I do introduce historical detail I try to work it into the action and narrative in such a way as to not draw undue attention to it.

For example, you may have a scene where your protagonist inspects some lines on her face as reflected in a mirror. Some detail about the mirror and the source of illumination (candle light, oil, kerosene, gas, electricity)can reveal much about the time and place of the scene, but those technological details must never crowd out what’s of primary importance: What does that look into the mirror reveal about the character and how does the scene connect to the story-line?