We see them every day. Posters advertising rock shows, plays, fragrances, food stuffs, cell phones, military recruiting and all matter of ephemera. Plastered on telephone poles, in storefront windows, and along the sides of buildings — they’re everywhere. And though eye-catching, they often are noticed with only a passing glance. This is unfortunate.

Upon close inspection, art and artistry is revealed. From rough-around-the-edges, do-it-yourself handbills to impressive glossies designed by graphic and fine artists, a beauty can be found. Aesthetics notwithstanding, they are not long for this world — at least in theory. These posters are all disposable; created not as art, but as utilitarian devices to be posted then discarded or pasted over when the event or promotional campaign is through — something that has marked them since their popularization in the late 1800s when the father of poster art, Jules Cheret, perfected the full color printing process.

Many of these posters survive, of course, and some have become highly collectible. Rarity, historical significance and pedigree bring top dollar on the open market.

Chicago becomes ground zero for poster collecting this weekend when the 2011 Chicago International Vintage Poster Fair opens at the Chicago Cultural Center. Now in its 21st year, the event (which also runs each fall in New York City and San Francisco) gathers twenty-two of the most important poster dealers in the world under one roof. Five to ten thousand posters will be for sale, ranging from French dancehall and war posters designed by masters Toulouse-Lautrec, Picasso and Matisse and World War I and World War II propaganda pieces to early transportation adverts, Art Deco wonders, circus posters and beyond. The variety is staggering.

Authenticity is vital. To ensure quality, each poster in the fair is vetted by the International Vintage Poster Dealer Association to ensure that it was created by a business for commercial use. Reproductions of any kind are forbidden, as well. Wall-sized Bob Marley dorm-room posters and fake Le Chat Noir prints stay home.

Posters are available at price points ranging from $200 to $15,000 — reasonable sums considering the artistic quality of the work. For folks not able to shell out such cash, the fair accommodates by being a browser’s paradise. Dealers shuffle their wares, as well, offering new posters each of the event’s three days.

Additional eye candy appeal comes via the fair’s annual theme: Sex sells. Walls of posters will spotlight the use of sex in advertising throughout poster art history, from the male-focused, female-heavy ads from the 1890s and early 1900s through the equal-opportunity sexiness of more contemporary advertisements. Va-va-va-vooom.