There's little nostalgia for the days of the Great Depression, yet one bygone of the era has made an astonishing comeback: the glassware that bears its name.

Depression glass is the mass-produced table and kitchenware that flooded the market from the 1920s to 1940s. Today, experts say it is the number one collectible. In some ways that's surprising—where most antiques are treasured for their rarity or quality, Depression glass was made by the millions on and on the cheap. The manufacturing process employed the same kind of low-grade glass used in commercial bottles and jars, and it also suffered the same results; bubbles, dents and ripples. In its day, the public forgave these imperfections, which were a small price to pay for its small price tag. Even in an empty-pocked era, Depression glass fit into most working-class budgets. The flaws are now hallmarks of authenticity, central to its charm.

The real lure of Depression glass—what captivated Americans then and enchants them now—is the stunning array of patterns and kaleidoscopic colors. American glass manufacturers created dozens of patterns, ranging from plain to playful to elegant, and many of those patterns came in a Crayola crayon assortment of colors that continued to fill cupboards right up until the Second World War.

Even in hard times, the price of Depression glass was right—in fact, it was often free. Buy a 25-pound bag of flour and you'd find a cake plate packed inside. A box of cereal would get you a cobalt blue Shirley Temple milk pitcher. A new dish set came with a new bedroom set, on the house. Businesses used any incentive they could to entice consumers to buy their products. The notion that any of these giveaways could ever become more valuable than the product they were peddling was unimaginable. One of the more indelible memories of the time was "Dish Night" at the movies. "The movies is what when I remember most," says glass authority Doris Yeske, a Depression-era youngster. "After going to a double feature for 30 or 40 cents, you'd receive a colored bowl. That's how my mother obtained most of the glassware she had during that period." Her mother's dishes became the foundation of her own collection. Today, Yeske, author of Depression Glass: A Collectors Guide has over 3,000 pieces in her collection.

Americans augmented their free cups and plates at stores like Montgomery Ward and the neighborhood five-and dime. The range of Depression glassware was exhaustive, from tea sets and punch bowls to candlesticks, juice reamers and berry bowls. Dining was an integral part of "family recreation," Yeske says. Homemakers took great pride in setting gracious tables and the glassware reflected the fashion of that time. A table set in sparkling colored dishes "brightened up that whole drab period."

In time, Americans grew tired of colored glassware and crystal gained in favor. Consumers also found themselves in a position to afford higher quality settings. As Depression glass lost its luster, thousands of pieces wound up boxed in attics where they would stay, in many cases for decades.

It took a generation or two for collectors to rediscover Depression glass, and even longer to appreciate it. For years, those sets that weren't packed away were being sold for a song at flea markets and rummage sales—that is, until a Springfield, Missouri, woman with an eye for the glassware and a strong sense of curiosity decided to do some detective work. Hazel Marie Weatherman, a pioneer researcher in the field who died in 1997, was among the very first to document the patterns, colors and manufacturers of the period glassware. In 1969, she published A Guidebook to Colored Glassware of the 1920s and 1930s. Suddenly thousands of people realized their pretty etched plate or orphaned sugar bowl had a history. By publishing her findings, Weatherman achieved respectability for Depression glass and set off a buying frenzy across the country that has yet to let up. Children of the Depression, now middle-aged, went back to their attics and opened up a Pandora's box of memories. Many of their children found themselves taking up a new pursuit.

The challenge for today's collectors is in matching and completing sets. More glass was manufactured during the Depression years than any other time in history. Despite the massive output, Depression glass was, in a sense, a victim of its own popularity. Few entire sets, and fewer still in mint condition, survived years of everyday use.