My time to shine There are a handful of books that are good and some that are not so good. What People Wore When by Levinton is good to get a very, very basic idea. The illustrations are a close approximation of the times and cultures they represent and give a good idea of the silhouettes worn, but they sort of glaze over the diversity present at any given time.

The Cut of Men's Clothes and The Cut of Women's Clothes by Waugh, as well as the Patterns of Fashion books by Arnold are much more in-depth and explain how things were really made, but they only cover about 1600 to 1900. If you're interested in the 20th Century there are a million great sources.

The internet is unfortunately a pretty bad source, there are lots of little home made sites people have put together that aren't well-sourced and make really broad claims. Wikipedia has a little fashion page for most periods like this that are decent starting points.

The absolute best way to learn about the history of fashion is to look at primary sources; either extant pieces, art pieces, or writings about clothing from that time period. Most costume historians tend to also study either literature or art history at least a bit. The Met museum has a gigantic collection of images of real pieces available online, and if you can access it Artstor is an even bigger database of images.

If you want to know more about a specific time period let me know, otherwise my suggestion would be to get your hands on a broad overview book or start poking around in the wikipedia pages, then go from there. Look out for artists' names especially, look them up to see other examples from whatever culture they're depicting, see what related artists were doing, etc.

Any particular time period? I have a literal library, so that's a lot to list.

Janet Arnold's Patterns of Fashion series

V&A Historical Fashion in Detail

Seventeenth Century Women's Dress Patterns I & II

The Tudor Tailor

Norah Waugh's The Cut of Women's Clothes or The Cut of Men's Clothes

Cunnington's The History of Underclothes

Doyle's The Art of the Tailor

Waugh's Corsets & Crinolines

Hi, I'm coming late to the party, but I wanted to add my $0.02. The other users have given you some good starting points if you're curious about the construction of historical clothing and focused study on extant clothing of a particular era, but it "sources on the history of fashion" sounds more like you're interested in a broad approach to historiography. So, here's my suggestions in case that's what you were aiming for...

For a drinking-from-the-fire-hose approach, I recommend Survey of Historic Costume by Phyllis Tortora & Keith Eubank. I have taught fashion history survey classes from this book and it's not a bad place to start. There's a lot of generalities and skipping over nuances, but it's trying to give a broad approach to fashion history. It is also regularly updated, so it isn't liable to get outdated as quickly as other survey books can become.

There's also 20,000 Years of Fashion by François Boucher. This is an older book and out of print, but I've used it as a good starting point for many years.

For scholarship on the cultural and historical significance of the corset, you can't do much better than The Corset: A Cultural History by Valerie Steele. Basically, anything written by Steele is pretty solid, from a scholarship standpoint, and she's the go-to source for anything related to corsetry.

Medieval: Fashion In The Age of the Black Prince by Stella Mary Newton is the seminal work in the area of fourteenth and fifteenth century clothing.

Renaissance: Maria Hayward's Rich Apparel is an incredible resource if you're at all interested in drilling down into the socio-economics of Tudor fashion--and it's highly readable.

Early Modern: Aileen Ribeiro's Fashion & Fiction is a killer book that focuses on clothing in art during the seventeenth century, but she has many more books on other eras that are equally as good.

Ancien Regime/Long Eighteenth Century: Daniel Roche's Culture of Clothing: Dress and fashion in the ancien regime is a must-read, but it is pretty dense as well as being a translated work from French to English (though this particular translation is pretty good).

Similarly, Caroline Weber's Queen of Fashion is a must read if you're interested in the fashion and fashioning of Marie Antoinette.

Critical Theory: Anne Hollander's Seeing Through Clothes pretty much saved my bacon in grad school.

That covers the basics of the period you mentioned wanting suggestions for. If you have any more questions, just PM me! I'm always happy to talk clothing history.

Edit: Forgot that Amazon links can be marked as spam, so I replaced all the links to Worldcat entries.