The busiest shopping season of the year is underway in the United States. According to the National Retail Federation, 25 percent of all retail spending in the United States each year takes place during the holidays. And while it's a major business opportunity for merchants, and an exhausting chore for many consumers, author Thomas Hine believes holiday shopping also reflects a time honored human need. He explains why in his new book, I Want That! How We All Became Shoppers.

Visit an American shopping mall during the holiday season, and you're likely to find big crowds and reluctant shoppers. "In general I don't like shopping. I only shop when I need something specific. I enjoy the scenery and the decorations, but I don't like a lot of shopping," says one woman.

"Shopping can be fun but it can also be a hassle," says a man. "It's a little bit like doing taxes when you think about it. It's a lot of work."

"I don't love to shop, but one wants to give gifts to special friends and family, so I will be doing some shopping later," another woman says laughing.

Complaining that holiday shopping has become too time consuming, too costly, and too stressful has become almost a holiday tradition in itself. But in his book I Want That! author Thomas Hine argues that shopping is part of what gives the season its meaning.

"Gift giving is one of the most ancient of human activities, and the reason Christmas is so stressful is it really forces us to look at the relationships in our lives, to see who we care about, and how we want to embody those relationships in something we can buy at the store," Mr. Hine said.

Thomas Hine has written extensively about shopping over the years, and he's found the subject makes people uncomfortable. They don't like to admit they enjoy browsing in stores or acquiring new things. But he believes most people have an innate need to shop. "It's really a way of trying on identities and helping us figure out who we are," he theorizes.

Shopping seems to be one truly international subject.

"We saw that spectacle not that long ago when the Taliban fell in Afghanistan. The next day everyone went shopping. And of course that happened in Eastern Europe in 1989. Shopping isn't a substitute for political freedom. But it does relate to a kind of freedom that's very important in Western society, and especially in American society, which is the freedom to invent yourself. And from the very beginnings of the human species people have been using objects both to symbolize and also to assert their power over the world and over other people," Mr. Hine said.

From the first informal exchange of prehistoric goods to the thriving markets of ancient Greece, shopping has always existed in some form. But Thomas Hine believes the European roots of today's shops, department stores and malls date back some 500 years to the Renaissance.

"You had a number of powerful cities where there were royal or ducal courts or institutions like the Vatican. And shop districts grew up of people who made clothing, armor, hats, boots - all of the things that were necessary for people to present themselves or assert their power in these courts or other institutions," said Mr. Hine. "Once the beginnings of industrialization started happening in the 18th century, more and more people were able to acquire items that previously only very powerful people were able to have."

With the rise of shops came new incentives to buy. Those incentives included everything from the spread of inexpensive window glass to the 20th century explosion of media advertising.

"Storekeepers started doing displays in their windows, and suddenly in the late 18th century, in novels, we find the new phenomenon of the window shopper going around looking in the windows of stores and seeing what's available."

One consumer tradition merchants didn't encourage, says Thomas Hine, is holiday shopping. He believes that in America that customs dates back to the 19th century and the growing public enthusiasm for Christmas as a festive celebration involving songs, decorations, and lots of gifts.

"Stores would never have invented Christmas in the sense that it involves too much activity in too short a time," said Mr. Hine. "It's difficult for keeping their stock, for making orders, for staffing. Also, it basically means their profitability depends on a terribly short time. But what happened was that the merchants had to keep up with an increasing enthusiasm that was really coming out of the household for celebrating this festival of the family."

Whatever the time of year, Thomas Hine said shopping has become more impersonal over the centuries. More and more shoppers are turning to huge stores, mail order catalogues, or the Internet, where they have little contact with sellers. But he also notes that one of the biggest shopping successes of recent years has been eBay. The on-line auction house offers a chance to interact, bargain, and discover the unexpectedall the things that have traditionally made shopping so enticing.

"The future of shopping to me is very likely to be the past of shopping, making use of new technologies that enable some of the dreams we've had over the years to be more effectively realized," he said.

After years of writing about consumer habits, Thomas Hine said he considers himself an educated and enthusiastic shopper, except around Christmas.

"I panic a few days beforehand and run and buy a few gifts, although this year I think I may be giving a lot of copies of 'I Want That!'" Mr. Hine said.