Courtesy photo.

Whether she's wearing an easy J.Crew shift and cardigan or a bright Thakoon dress, Michelle Obama is known for her unique, truly fashionable fashion statements. A new book that's now out, "Everyday Icon: Michelle Obama and the Power of Style," looks into the first lady's look, what it represents and how it sets her apart from predecessors in the White House.

StyleList caught up with the book's author, fashion journalist Kate Betts, about what makes Mrs. Obama a stand-out.

StyleList: What made you decide to write about Michelle Obama and her sense of style?

K.B: I always like to look at fashion against a broader cultural context -- this seemed like an incredible opportunity to do that. I thought this was a great story to tell because I had wanted to talk about the difference between style and fashion and why style matters. I needed a lens, and she was the perfect lens.

StyleList: How has her style evolved since she's been in the public eye?

K.B: When she started on the campaign trail, her image was much different. She was a corporate success story: She wore pinstriped pantsuits and was kind of hard-edged in her appearance. You could see a definite change -- a very calculated, conscious change -- from the corporate mother to the mom in chief.

That was the Jay Leno moment: the J.Crew outfit and the whole idea of how little it costs, against the backdrop of Sarah Palin. It was interesting to see how much appearance plays a role in politics.

StyleList: It's ironic that the "calculated" look, with comfy cardigans and breezy dresses, looks so effortless.

K.B: It was totally effortless, and totally effortless on purpose. I think part of that is her style -- she knew what she had to do. She also tapped into something in herself that was much more about being a mother and a wife than being a successful career woman.

StyleList: Wearing accessible brands like J. Crew and Talbots has become one of her trademarks. Why do you think that's been so impactful?

Courtesy photo.

K.B: That shows the power of her style. People don't have access to the first lady or the president --- they communicate with the people (and I mean the greater public) through their image. That Inauguration Day when she held up her hand to wave and she was wearing the green J.Crew glove -- anybody in America can go to J.Crew. It's everywhere, everybody knows what it is: It's not some researched thing that is only special to the first lady. It really brought her into everybody's world in a very concrete way.

StyleList: It made her seem real, like someone you'd know.

K.B: Yes, exactly. And it's in those little details the message is conveyed. It's easy to say, I'm real, I'm a mom. Nancy Reagan was a mom too; so was Jackie (Kennedy). This was a very different message. Michelle is really the postfeminist icon. She's the one who says, I'm not going to struggle anymore -- I'm just going to throw up my hands and say, You can't have it all, all of the time. She's revisiting this idea that women have to live up to the standard of having it all. She has a much more relaxed place, in a way, in our minds when it comes to our projections of what we think she should be as a woman.

StyleList: Mrs. Obama has also championed designers like Thakoon, Jason Wu and Isabel Toledo. Why has that been important?

Courtesy photo.

K.B: That's very symbolic. It's like, Here we are in an administration that is promising new faces, change and a whole new approach to governing. She's mirroring that message with her appearance and her images. And that makes perfect sense when you think about it. Why would she be dressed by one exclusive designer, and why would that designer be somebody that has nothing do with her generation?

StyleList: There's a great quote in the book from Michael Kors: "She's letting women know that the word appropriate has changed." How has Michelle Obama changed it?

K.B: The fact of the matter is, in many ways Michelle Obama is challenging the rules and rewriting them. She is changing protocol. You would think as the first African-American first lady, she would probably tread more carefully and be somebody that wants to stay in the background and fit in, but she's taking the counter-intuitive approach. She's standing out more than she already does stand out. I think that's an incredibly bold and very effective move on her part.

For more of Obama's iconic looks, check out the gallery below.