As befits a blog on living single, I've written quite a lot about living alone. The increase in the people going solo, in the US and in many countries around the world, has been nothing short of extraordinary.

Yet as I traveled around the country to learn how people are living now (for my new book, How We Live Now: Redefining Home and Family in the 21st Century) and read heaps of studies and statistics, I learned something else amazing. There are even more people in the US who are living with other people – and that's not including anyone living with a spouse or romantic partner! About 41 million Americans fit that description, compared to about 34 million who are living on their own.

Many of the people who are not living with a spouse or romantic partner are living with family. They inhabit all sorts of "lifespaces," from sprawling multigenerational or extended family households to single-parent households to spaces shared by siblings to places that are home to combinations of friends and relatives, adults and children, so creative that they defy classification.

Sometimes families double up, but not across the generations or across the same generation of siblings and cousins and such. Families come together who have no biological ties whatsoever. For example, did you know that if you are a single mother and you would like to live with another single-mother family, you can find about 70,000 others just like you at CoAbode? Until I started working on How We Live Now, I had no idea there was such a vast network of like-minded single mothers and that they have a place online to come together and find one another.

Also growing is the number of shared households in which there are no spouses or romantic partners and no family, either. We usually think of those households as filled with college students and other young adults, but that way of living has becoming increasingly popular across the entire adult lifespan. The Golden Girls have contemporary real-life counterparts.

Here are just a few of the fun facts I learned about shared housing while researching How We Live Now:

In the 19th century, up to half of people living in cities were either living in a boardinghouse or running one. The commune from the countercultural era that has endured the longest without interruption is Twin Oaks, in Louisa, Virginia. That's the one based on B. F. Skinner's popular novel, Walden Two. In 1950, only 1.1 percent of all households were comprised of two or more unrelated people. By the turn of the twenty-first century, 6.1 percent of households were in that category. The biggest increase from 2007 to 2010 in living with unrelated adults was the group of twenty-five-year-olds through thirty-four-year-olds. When AARP asked women who were 45 and older to explain the appeal of sharing a home with friends, nearly 90 percent said that it was the companionship that was most attractive.

My initial for researching the way we live now grew out of my interest in how single people are living. Once I got into the project, though, I discovered that couples and families were innovating in intriguing ways, too. In a future post, I'll have more to say about couples who are living together and apart.

[Notes: (1) Today, August 25, 2015, is the official publication day of How We Live Now: Redefining Home and Family in the 21st Century – that's probably exciting only to an author; (2) If you are interested, you can learn more about How We Live Now at this page of my website, where I post updates. I also have a Facebook page for the book. I'm on Twitter now, too. (3) Vicki Larson interviewed me about my new book; that Q & A is at the Huffington Post.]