Gretchen Rubin’s “Moment of Happiness” email comes every weekday between 8:01 and 8:07 am. I almost always check the message on my BlackBerry and scroll down to see the quotation, about 20 words of insight into human happiness. On August 30 there was advice from Emerson: “Write it on your heart that every day is the best day of the year.”

Rubin is the author of the bestselling book “The Happiness Project,” in which she chronicles a year of tweaking her daily routine in the hopes of becoming a happier person. In September 2012, Rubin published “Happier at Home,” a similar work that applies the same themes to domestic and family life. The book hit number two on the New York Times bestseller list within a week of publication.

Happy and They Know It — Rubin’s Readers

Photo by Elena Seibert

Over the past few years, life satisfaction has become the cool thing to aspire to. In 2008 the American Psychological Association estimated about 2,000 total self-help titles were sold yearly. Though Rubin, 46, is hardly the first author to write about the quest for personal satisfaction, she’s by far one of the most popular. “The Happiness Project” has remained on the New York Times bestselling paperback advice list for 82 weeks straight. In the years since the publication of “The Happiness Project,” readers all over the world have started their own Happiness Project groups, in which young doctors, city moms, and everyone in between get together to read the book and make resolutions of their own.

“The Happiness Project” and “Happier at Home” are extremely personal narratives — sort of. Rubin outlines the comings and goings that make up her life as a writer and a mother, with the amount of detail that in a less well-written work, would make some of us cringe. (“One day, when I was standing in line to buy envelopes, I caught sight of a box of my favorite kind of pen: the Deluxe Uniball Micro.”) But Rubin leaves out the kind of dirt that some adult readers love — she never mentions how much money she makes, talks about her sex life, or sounds like she’s having a mid-life crisis.

In both books, Rubin comes clean about her quirks, the kind she assumed most people couldn’t relate to. She didn’t learn to drive until a few years ago because she was too scared. She has to cut herself off completely from sweets or else she’ll go overboard, a technique she calls “abstaining.”

I read the majority of both Rubin books standing on the F train. By the end of “Happier at Home,” I’d come to see Rubin as a kind of commute buddy, so much so that I started weirding people out around the office when I kept referring to my friend “Gretchen.”

Immediately after finishing “Happier at Home,” I emailed Rubin to tell her how much I enjoyed the book and to set up a time when we could meet. But a few hours later, a response showed up in my inbox: “Alas, I’m so swamped with my book coming out this week — could we do this by phone?” My heart sunk.

When I called Rubin to talk her books, I was a little surprised when two arms didn’t literally slide out of the phone receiver to wrap me in a warm hug. Rubin has a deep, almost serious voice, with the slightest Midwestern accent. (She originally hails from Kansas City, Missouri.) You can tell she’s smart — when I asked her even the simplest question, she’d pause for a few long seconds and come back with a pithy, well-thought-out response.

I asked Rubin why she thought happiness was so important and this time she paused for so long I thought she’d hung up.

“Happiness gets a bad reputation,” she said finally, and a lot of people think happy people are stupid or self-indulgent. Instead, Rubin told me, studies have found happy people are more altruistic and in fact less self-centered than less happy people. “If you think it’s selfish for people to want to be happy than you should be selfish if only for selfless purposes.”

All during our conversation I tried to refrain from shouting, “OMG Gretch, we are the same person!” After all, Rubin loves to read and so do I; her mother wishes she’d pay more attention to fashion and so does mine. We both typically prefer a nice dinner party to a wild night at a bar.

But Rubin, apparently, had heard it all before. “It’s totally amazing to me how many people said, ‘Oh, I’m exactly like you’ [after reading “The Happiness Project.]” In the years since she published “The Happiness Project,” Rubin said, she’s discovered “there are other people like that out there — abstainers, people who are afraid to drive.”

Rubin’s fans say those personal confessions are exactly what makes “The Happiness Project” a compelling read and an inspiration to get happier. I spoke to Dallas Stobaugh, a 29-year-old medical resident in a pediatrics unit who started a Happiness Project group in Philadelphia last year. “Reading about [Rubin] in her apartment with her two kids was actually more informative than a global statement about making time for your family,” she told me.

As part of their personal Happiness Project, Stobaugh and a group of five or six residents made a resolutions chart that included a daily tea ritual to ensure they were making time for socializing. On a night shift, she said, they have 3 am tea.

Sarah Stewart, who works in the financial aid office of an elementary school, started a Happiness Project group in Philadelphia before moving to Kentucky. She told me she thought she had a lot in common with Rubin. “[Rubin’s] just a normal person who deals with normal things,” Stewart said. “It was refreshing.”

Rubin makes a point of interacting with her fans, responding to the majority of comments on her blog posts with multiple thank you’s and exclamation points. Every Wednesday she posts a “Pigeon of Discontent” video, in which she sits in an elegant living room and answers readers’ questions about how to stop using the snooze button, or what to do when you feel people take you for granted. No question seems too trivial or too serious.

The World’s Happiest Woman — Rubin’s Life

In “The Happiness Project,” Rubin talks about some of her favorite activities: reading, learning, and organizing her notes in stacks of index cards. Her nerdy side may be another factor in the books’ success, especially among mental health professionals. Dr. Sonja Lyubomirsky, whose research Rubin cites in both books, told me she was thrilled that Rubin “did actually read the science.” A lot of self-help writers, she said, only read what someone else has written about scientific studies.

But Rubin is no average quirky book nerd. A 2010 New York Times profile made a big deal over the fact that Rubin is relatively wealthy — her husband James Rubin is an investment banker and her father-in-law Robert Rubin is the former Treasury Secretary. A Kirkus review talked about Rubin’s “privileged, relatively-trouble-free home” and said she was “out of touch” in her books.

While negative criticism of Rubin’s work is few and far between, she’s probably developed a pretty thick skin. Rubin went to Yale Law School, where she met her husband, and clerked for Justice Sandra Day O’Connor. Though she says she doesn’t regret going to law school and describes clerking as “amazing,” Rubin admits she “did not choose law school mindfully.”

Neither she nor her husband works in law now, and Rubin writes in both books about finding her true passion in writing. Before “The Happiness Project” turned her into a self-help celebrity, she wrote several biographies and other books on political topics, none of which did especially well.

But Rubin seems to have found her calling in happiness, and helping other people find it. Towards the end of our conversation, Rubin made her final case for happiness.

“It’s the natural desire of human nature to seek to be happy,” she told me. “You’re just happier when you’re happier.”

To learn more about Gretchen Rubin, check out her blog

Have you read “The Happiness Project” or “Happier at Home?” What did you think? Let us know in the comments below or get in touch with the author @ShanaDLebowitz.