The History of Underclothes
For more detail about the Victorian period in the United States, there's the 1886 Bloomingdale's catalogue.
Still, this gives you a good idea of the sorts of clothing people from the period would wear. It also includes information on underclothing. (So much of it!) There's a whole section on corsets. Plus pages on children's clothing and all sorts of other merchandise.
For stories set in the medieval period, there are several works by Joseph and Frances Gies.
I have these two books, but there are several more. They give great detail about what medieval life was like. It turns out castles were a lot more comfortable to live in than one might think. Americans need to bear in mind that the climate in Europe is usually not as extreme as our own.
I might have to go back and buy some more books, come to think of it.
By the way, when I want to buy used books online, I generally go to http://www.abebooks.com/. It's a listing place for huge numbers of independent used book sellers. You might get your book from Vermont or Oklahoma. I've always had great service from these merchants.
Finally, here's something rather idiosyncratic to me. http://www.sciencetimeline.net/
My training is in social science, specifically psychology. I enjoy writing characters who have an interest in science. I love to look at the science timeline from around the year I'm writing and see what work was being done and what theories would have been in the air.
Did you know that in 1751, Benjamin Franklin published the results of his experiment with the kite in a paper titled Experiments and Observations on Electricity? Or that in 1733 someone named Hales measured blood pressure? I've had all kinds of fun with Gall's theory of phrenology, which posited that mental functions each had their own location in the brain and those functions could be measured through bumps in the skull. I could get lost in the timeline for hours.
What are your favorite research materials?