For more than 20 years, Colin McDowell has been one of the fashion industry's leading commentators, most notably for the Sunday Times Style, though he's also published 22 books on a range of topics; from biographies of Ralph Lauren, Manolo Blahnik, and John Galliano (whom he also taught in London) to definitive fashion references, the latest of which—The Anatomy of Fashion: Why We Dress the Way We Do—available now from Phaidon.

The comprehensive resource (McDowell prefers the term sexy read)—the result of years of extensive research on the history and physicality of fashion—charts a beautifully illustrated course through the very beginnings of dress (back when our Cro-Magnon counterparts sported loincloths), tracing the evolution of trends in clothing, accessories, and grooming to the way we look today. While the book's time line alone will undoubtedly land it on more than few required-reading lists at fashion institutions, McDowell's obvious exuberance for the topic makes it an accessible and exciting read.

Details caught up with McDowell on a hot afternoon in London to talk about why men should wear skirts, the quiet revolutions that have changed menswear, and his predictions for the future of fashion.

DETAILS: In the book, you explain why we dress the way we do, but for those of us who don't want to read all 260 pages, is there a simple answer to that question?

Colin McDowell: There's a simple answer, but it's complex at the same time. When I'm talking to young people, I always say, when our ancestors in prehistoric times killed the first wooly mammoth and took the skin—it was then that they invented clothes. When they killed the second one and they took the skin again, they invented choice. Both of which are very, very important, in fashion and in dress. But it wasn't until we discovered that we could see ourselves in reflective surfaces that we really understood fashion, because it was only then that we could see the way we looked.

That, of course, brought about vanity, and vanity is really what it's all about. Vanity, self-approbation, the approval of others—they all come under the same heading, in my opinion. We care about what others think of us, no matter what we might say to ourselves and to others. We care about the way people view us, and that means we care about our appearance.

For example, it's a very hot day here in London. If there was an edict from the Queen or from Parliament saying, "Okay, it's very hot. You can all walk down the street with no clothes on and you won't be arrested," very few people would do it, because we have great insecurities about our looks. It all seems to be built into our DNA. We are insecure about how we look. I look back and I think that prehistoric men can't have had these insecurities, because they didn't know how they looked.

DETAILS: Phaidon is calling this "the most comprehensive source book on fashion ever." How did you go about researching some of the more obscure and historical elements?

Colin McDowell: For a long time I've been thinking that it's all about the body and insecurity, and I decided the thing to do was to look at the body in all different eras and see how elements have been exaggerated, approved of, tried to be hidden, disapproved of—particularly by the church and moralists—and that's how it all started.

I didn't want it to be a fashion book, per se, and I didn't want it to be a costume book, a history book, or an anthropological book—I wanted it to be, in part, all of those things. And that's what I think we've done. You'll see that the pictures are exceedingly wide-ranging. As a picture book it's fantastic. I'm terribly proud of the time line as well. I personally think it's the most comprehensive and most well-illustrated time line that we've ever had.

I'm sure you're thinking, "Well who the hell is going to read this book?"

DETAILS: Yes! That was the next question.

Colin McDowell: I really think it will have a very wide readership. Not just for people who need to quickly check things, but also families. I like to think it's like Webster's dictionary, and every household has a copy. I'm joking, of course.

DETAILS: So it's primarily a reference book?

Colin McDowell: I think it's a very clever, well-researched reference book. I say that because it's all been very carefully edited by the people at Phaidon because they think it's a book that people will want to keep referring to for quite a long time. I'd hate for it to be called just a reference book, though. It's a sexy read!

DETAILS: In terms of the time line, can you point to some of your favorite fashion eras?

Colin McDowell: Oh boy, how long have you got? They're not always really fashion periods, they're periods when clothes had a particular significance and importance. I'm thinking particularly here of the 16th century in England, Spain, and Italy, when clothes were incredibly complicated and unbelievably expensive. One court's dress would cost the equivalent of several very expensive houses. These clothes…weren't about fashion; they were about display. They weren't saying, "Don't I look sexy?" They were saying, "Don't I look powerful?" This was a really big show-off period in clothes. Of course, there were others that came later.

DETAILS: What era are we in now?

Colin McDowell: When fashion becomes very stupid, as it did at Versailles, where people were running around like headless chickens trying to see what was the next thing, it always ends in disaster—and it did with the French Revolution. I sometimes think we're in a Versailles moment, because we're all crazed by fashion. There's the latest name, the latest look, the latest trainer. It's an obsession with trivial things that make us feel better, and I think that there's every possibility that it might actually end in a few years' time in some sort of Versailles collapse.

DETAILS: What about a least favorite period?

Colin McDowell: The Twenties. From the point of view of fashion, I think they were very, very boring. The clothes were so simplistic, so silly, but they were deeply important, because they were the first clothing that could be said to be "modern" and to treat a woman as a modern person who if she wants to jump over a gate, could jump over a gate; or if she wanted to run for a bus, she could run for a bus—just like men had been able to do for much longer. So they're terribly boring. Because what is more boring than a little shift dress? Nothing. But what does it stand for? Everything.