How could a woman in a bright blue jacket and pink tights possibly be unhappy?

Alexandra Stoddard is a walking advertisement for the subject of her new book, Choosing Happiness (Harper Resource, $22.95), a slim blue volume with a fuchsia anemone on the front.

“My message is that happiness is the first principle of life,” says Stoddard, calling in from a book tour that has her zigzagging cross-country. “But you must choose it. We all have pain, but suffering is a choice. You can be happier if you make some changes in your life.”

After an almost 40-year career at the upper reaches of New York interior design, this author of 22 widely popular books has become an expert on creating homes that are pretty in the service of promoting inner peace.

Stoddard, 60, possessor of a sunny personality and girlish energy, makes an ideal cheerleader for happiness. Her message has proved on target for the times, finding an audience among mainly female readers short on time and long on tension.

She advocates making time to light a candle and have a cup of green tea, even if you have to log it into your Palm Pilot to make it happen. The advice dovetails nicely with the current thirst for spirituality expressed in the teachings of holistic healing guru Deepak Chopra, aromatherapy, feng shui, Zen gardens and Oprah’s soul-soothing magazine.

Her new book combines simple decorating ideas illustrated only with philosophical exhortations to seek a more contented domestic life. Sprinkled throughout are encouraging quotations from unexpected notables: Marcus Aurelius (“Remember this, that very little is needed to make a happy life.”); Alistair Cooke (happiness is “the opportunity to do good work, to fall in love, to enjoy friends, to sit under trees, to read, to hit a ball, to bounce a baby”).

Stoddard became nationally known with her 1986 book, Living a Beautiful Life: 500 Ways to Add Elegance, Order, Beauty and Joy to Every Day of Your Life. Her advice on polishing brass for pleasure and arranging a guest room with fresh roses and starched linens seemed to click among readers more likely to own no-iron. It sold more than 1 million copies.

Stoddard, however, is no Martha Stewart. Her writings emphasize over and over that beauty is achievable without hours spent gilding acorns for holiday wreaths. (But she might suggest finding a spot for them on your desk in a basket tied with a lime-colored ribbon.)

After graduating from the New York School of Interior Design on a full scholarship, Stoddard began her career at McMillen, one of the country’s oldest interior-design firms, headed by Eleanor McMillen Brown. When Brown retired in 1977, Stoddard started her own firm and has since been published in virtually every design magazine, decorated rooms at the Kips Bay Show House and hosted a show on HGTV.

Stoddard insists she is still old-fashioned in many ways; she carries no cell phone and does not use a computer. But she does have a Web site with a monthly newsletter that keeps tabs on where she and her husband, lawyer and author Peter McGargee Brown, have been traveling and what’s new in their Park Avenue apartment and Stonington, Conn., cottage ( .com).

Wherever she lectures, Alexandra Groupies flock to drink in every detail. Some even teach classes on how to live beautifully the Alexandra Way. (It might involve boxes of scented soaps and bright-colored underwear.)

This book, five years in the writing, had been sent in to the publisher when the Sept. 11 terrorist attacks happened. The author was able to insert a few paragraphs into the introduction to focus attention on the importance of hope and happiness.

“The timing of this specific book is absolutely perfect. It struck a chord. We all are ready to turn the corner and achieve happiness again, especially in New York and Washington,” says Jane Friedman, president and CEO of HarperCollins publishers. “The way the book looks, the short takes, the plain speak, the two colors on the cover: It’s all very comforting, and very Alexandra.”

Friedman herself seemed ready for an Alexandra fix. “I’ve had a tense morning, and I feel like I could read a few of the quotes in the book and take a deep breath.”

Here’s our conversation with Stoddard:

Q. How did you first get into decorating?

A. I love people and care about them, and I felt I had a gift to cheer people up. If I could get into their homes and make their environment more attractive, they’ll be happier and it would be very rewarding for me.

Q. Why did you do this book?

A. This book makes you happy. Every doctor studies unhappiness. Very few people think about happiness, and they don’t take courses in it or tell their friends about it. They think of their raises, promotions, kids’ schools, etc. We are not raised to think about our happiness.

Q. How did you become an expert on this?

A. I have been making house calls for years. Being a decorator allowed me to see what about people’s environments made them happy. And what things they could do to have more light and color and joy in their daily lives.

Q. How is your home tied up with happiness?

A. The home is the center of your soul; it’s a total reflection of your inner life. If you have a dreary home, it means you are dark inside. It has nothing to do with money. Of course, money can help you buy curtains. But there is no good taste or bad taste. Your home should reflect where you are in your journey.

Q. Why was Living a Beautiful Life such a hit?

A. That book was about ritual, celebration and ceremony. It taught us that the smallest thing makes a big difference. Sometimes, you just have to clean out your tote bag, you know what I mean? Buy a bunch of tulips. You can spend a large amount on decorating, but you’re not truly living. You’re just waiting for the next dinner party.

Q. Are your fans like Martha Stewart’s fans?

A. No, Martha’s fans aren’t my fans. Of course, there is an overlap between anyone who is trying to make people’s lives better in the realm of lifestyle and contemporary philosophy and the home. Martha’s fans are more interested in perfection and trying to make their home party-ready and perfect. My readers are trying to grow and live a deeper, much more meaningful life. People call me the Julia Child of decorating. I know how to make it work.

Q. What special things do you do to make you happy?

A. People need to find their own preferences, but I offer simple suggestions that changed my life. The smallest little thing. I like pretty place mats. Checkered cotton tablecloths. Colored napkins with chartreuse and fuchsia flowers. I like drinking out of a stemmed glass. I make myself cinnamon toast and tea. I arrange flowers. I must have flowers.

Q. I understand you have a “flower fund” for budgeting your monthly expenses at the local flower shop.

A. Yes. I find that flowers are more important than food. I don’t spend as much on them, of course, but I do have a weekly fund. I don’t want to admit how much!

Q. How do your ideas affect your decorating?

A. I have been trying to make people happy all my life. I do little things for them in their homes that have to do with attitude and environment. But I can’t do it all for them because all I can do is let in more light, clean windows and fresh colors. I can’t live people’s lives for them. They have to turn on the lights and play the music themselves.

Q. Do you still have time to run a decorating business?

A. Yes, I have clients. Only happy clients though. Unhappy people are toxic.