Jeans are trousers made from denim. Often the term "jeans" refers to a particular style of pants called "blue jeans" and invented by Jacob Davis and Levi Strauss in 1873. Starting in the 1950s, jeans, originally designed for cowboys, became popular among teenagers, especially members of the greaser subculture. Historic brands include Levi's, Lee, and Wrangler. Jeans come in various fits, including skinny, tapered, straight, boot cut and flare.
The story of jeans begins in the city of Genoa, in Italy, famous for its cotton corduroy, called either jean or jeane; the jeans fabric from Genoa (at that time) was in fact very similar to corduroy. During the Republic of Genoa, the jeans were exported by sailors of Genoa throughout Europe. In the French city of Nimes, weavers tried to reproduce the fabric exactly, but without success. However, with experimentation, and through trial and error, they developed another twill fabric that became known as denim, literally "de Nimes". Only at the end of the eighteenth century did jeans arrive in the United States.
A young man named Levi Strauss immigrated in 1851 from Germany to New York to his older brother, who ran a dry goods store. In 1853 he moved to San Francisco to establish his own dry goods business.
In 1872, Jacob Davis, a tailor who frequently purchased bolts of cloth from the Levi Strauss & Co.wholesale house, wrote to Strauss asking to partner with him to patent and sell clothing reinforced with rivets. Davis' idea was to use copperrivets to reinforce the points of stress, such as on the pocket corners and at the bottom of the button fly. After Strauss accepted Davis's offer, the two men received U.S. Patent 139,121, for an "Improvement in Fastening Pocket-Openings," on May 20, 1873.
An oft-told "attractive myth" is that Strauss initially sold brown canvas pants to miners, eventually dyed them blue, turned to using denim, and after Davis wrote to him, Strauss added rivets to his blue jeans. However, this story is false and probably due to the discovery of jeans made of brown cotton duck, which was one of the early materials used by Davis and Strauss after 1873.  Finding denim a more suitable material for work-pants, they began using it to manufacture their riveted pants. The denim used was produced by an American textile manufacturer (popular legend states the denim was obtained from Nimes, France). 
Cost of jeans
In 1885, jeans could be bought in the US for $1.50 (approximately $36 in 2010). Today, a pair of durable jeans can be purchased in the United States for about 40 dollars. Designer jeans can be priced several hundreds of dollars, with some even approaching $1000. There is a robust market for used jeans, and the prices obtained for these pre-owned jeans vary tremendously.
Americans spent more than $14 billion on jeans in 2004 and $15 billion in 2005.
Evolution of the garment
Copper rivets for reinforcing pockets are a characteristic feature of blue jeans.
The blue denim fabric of jeans
Initially, jeans were simply sturdy trousers worn by workers, especially in the factories during World War II. During this period, men's jeans had the zipper down the front, whereas women's jeans had the zipper down the right side. By the 1960s, both men's and women's jeans had the zipper down the front. Historic photographs indicate that in the decades before they became a staple of fashion, jeans generally fit quite loosely, much like a pair of bib overalls without the bib. Indeed, until 1960, Levi Strauss denominated its flagship product "waist overalls" rather than "jeans".
After James Dean popularized them in the movie Rebel Without a Cause, wearing jeans became a symbol of youth rebellion during the 1950s. Because of this, they were sometimes banned in theaters, restaurants and schools. During the 1960s the wearing of jeans became more acceptable, and by the 1970s it had become general fashion in the United States for casual wear.
Michael Belluomo, editor of Sportswear International Magazine, Oct/Nov 1987, P. 45, wrote that in 1965, Limbo, a boutique in the New York East Village, was "the first retailer to wash a new pair of jeans to get a used, worn effect, and the idea became a hit." He continued, "[Limbo] hired East Village artists to embellish the jeans with patches, decals and other touches, and sold them for $200." In the early 1980s the denim industry introduced the Stone-Washing technique developed by GWG also known as "Great Western Garment Co.". Donald Freeland of Edmonton, Alberta pioneered the method, which helped to bring denim to a larger and more versatile market. Acceptance of jeans continued through the 1980s and 1990s to the point where jeans are now a wardrobe staple, with the average North American owning seven pairs.[verification needed] Currently, jeans may be seen worn by people of all genders and ages.
A typical pair of blue jeans consumes 919 gallons of water during its life cycle (this includes the water to irrigate the cotton crop, manufacture the jeans, and the numerous washes by the consumer). Because cotton is the world's biggest nonfood crop, and water shortages are a growing global trend, some jean companies are looking into ways to reduce the amount of water needed in their production of jeans-from field to factory.
Traditionally, jeans are dyed to a blue color using an indigo dye. Some other colors that can be achieved are pink, yellow, black, and white. These colors are achieved by coloring other fabrics to resemble jeans. Approximately 20 million tons of indigo are produced annually for this purpose, though only a few grams of the dye are required for each pair of these trousers.
Chemical structure of indigo dye, the blue of blue jeans.
For more information on dyeing, refer to denim and the discussion there of using pigment dyes.
Pre-shrinking of jeans
Young people wearing a variety of jean styles. (Rome, 2008)
In the 1970s Hal Burgess first marketed "pre-washed" jeans. He was a salesman for his father, who owned a large jeans manufacturing company in Cartersville, Georgia. While on a sales trip, there was a flood in the hotel room where Burgess was storing jeans. He asked the hotel owner if he could rent out the pool to wash the flooded jeans. The jeans shrank but Hal decided to market them as 'pre-washed' jeans and sold them two sizes smaller than they were initially labeled. This was the first time 'pre-shrunk' jeans were marketed.
On a national scale, Levi Strauss & CO. was the first to market pre-washed jeans on a nationwide basis, beginning in Oklahoma City & the C.R. Anthony CO. The CR Anthony Department stores were among the largest retailers of Levi Strauss. In 1980, young assistant manager at a store in Oklahoma City noticed a large number of men and, especially young women, asking to try on the returned jeans that had been returned for shrinkage problems. The assistant manager of the men's department, George Crosby, asked his manager and the upper management to place a double order for Levi 501 jeans for a marketing experiment. Getting the approval needed, Mr. Crosby & his fiance took the 100 or so unwashed 501 jeans to a local help-your-self "washateria" to shrink the jeans, re size & re label the jeans, and place an ad for a special offering of pre-washed 501's. The response was overwhelming. Within months pre-washed 501's directly from Levi Strauss were available regionally, then nationwide.
Used look created by sandblasting
Consumers wanting jeans that appear worn can buy jeans that have been specially treated. To give the fabrics the worn look, sandblasting is often used. Sandblasting has the risk of causing silicosis to the workers, and in Turkey, more than 5,000 workers in the textile industry have been stricken with this disease, and 46 people are known to have died. Some companies have announced they are banning the use of sandblasting. 
Care and wear
Despite most jeans being “pre-shrunk”, they are still sensitive to slightly further shrinking and loss of coloring from being washed. Because of this, jeans enthusiasts do not wash them often or at all. The Levi Strauss company recommends avoiding washing jeans as much as possible. Carl Chiara, Levi Strauss director of brand and special projects, has a credo: The less you wash your jeans, the better your jeans become. These and other suggestions to avoid washing jeans where possible have encountered criticism. Cory Warren, editor of LS&Co. Unzipped, clarifies in a response to such a criticism:
Our advice is to wash less often, but clearly, you have to judge for yourself what’s appropriate. Hot day, dirty job? Wash your jeans. Please! Cold day, office job? Maybe you can wear them twice or more before they go back to the washing machine. Personally, if I wear a pair of jeans to work on Friday — cool climate, office job — I tend to wear them on Saturday. And if Saturday is spent indoors and I’m not spilling food all over myself, I might even wear them on Sunday.