According to Wikipedia "Perfume is a mixture of fragrant essential oils and aroma compounds, fixatives, and solvents used to give the human body, objects, and living spaces a pleasant smell". The word "perfume" comes from Latin "per fume", meaning through smoke.
The art of making perfumes (perfumery) began in ancient Egypt and was later improved by the Romans and the Arabs. The process of extracting oils from flowers by distillation was introduced by an Iranian doctor named Avicenna. This is the procedure that is most commonly used today. The first modern perfume, made of scented oils blended in an alcohol solution was made in 1370 in Hungry and was known throughout Europe as Hungary Water. The perfumery continued to develop in Renaissance Italy and from 16th century also in France. The cultivation of flowers for perfume essences grew into a major industry in the southern France. Today, France remains the center of the European perfume design and trade.

The exact formulas of fragrances are kept secret by designer houses. However, some perfume experts can identify components and origins of scents in the same way as wine Testers.

Perfume classifications
In general, perfumes can be classified according to their concentration level and the notes of scent. Perfume oils are diluted, mostly by ethanol or a mixture of ethanol and water because undiluted they can cause allergic reactions or damage to the skin and clothing. Here is the perfume concentration level chart:
Pure perfume: 20 - 40 % aromatic oils
Eau De Parfum: 10 - 30 % aromatic oils
Eau De Toilette: 5 - 20 % aromatic oils
Eau De Cologne: 2 - 5 % aromatic oils
Fragrance houses assign different concentration levels for the same perfume category. An Eau De Toilette from one house may be stronger than an Eau De Parfum from another. There are three different classifications of perfume according to their scents: traditional, created around 1900, modern, since 1945, and so called Fragrance wheel created in 1983. The Fragrance wheel is widely used in the retail and the fragrance industry today. There are five standard categories: Floral, Oriental, Woody, Fresh, and Fougere (with the Fougere family placed in the center of this wheel since usually contain fragrance elements from each of the other four families).
Perfumes are described also by its three notes: top, middle and base. The notes unfold over time, with the immediate impression of the top notes, then the deeper middle notes and finally the base notes gradually appearing as the final stage. These notes are chosen very carefully with knowledge of the evaporation process of the perfume. Top notes are perceived immediately on application of the fragrance and thus, they are very important in the selling of the perfume. Middle and base notes together are the main theme of the perfume.

Sources of essential oil.
Barks: Commonly used barks are cinnamon and cascarilla and also sassafras root bark.
Flowers and blossoms: These are the largest source of aromatic oils. Rose, jasmine, osmanthus, mimosa, tuberose and blossom of citrus and ylang-ylang trees are commonly used in fragrance industry.
Fruits: Fresh fruits like apples, strawberries, and cherries do not yield odors well and usually are obtained synthetically. Exceptions include litsea cubeba, vanilla, and juniper berry and the most commonly used oranges, limes and grapefruit.
Leaves and twigs: Commonly used are lavender leaf, patchouli, sage, violets, rosemary, and citrus leaves.
Resins: Commonly used resins in perfumery are labdanum, frankincense, myrrh, Peru balsam, gum benzoin and also pine and fir.
Roots, rhizomes and bulbs: Iris rhizomes, vetiver roots are very often used for perfumes.
Seeds: Tonka bean, coriander, caraway, nutmeg, mace, cardamom and anise.
Woods: Very important in providing base notes. Commonly used woods include sandalwood, rosewood, agarwood, birch, cedar, juniper and pine.
Ambergris: Commonly called "amber" is obtained from Sperm Whale.
Castoreum: Obtained from the odorous sacs of the North American beaver.
Civet: Obtained from the odorous sacs of the civets (family of Mongoose).
Honeycomb: Distilled from the honeycomb of the Honeybee.
Musk: Originally obtained from the musk odorous sacs from Asian musk deer, but now replaced by synthetic musk.
Lichens: Lichen is a sort of fungus growing in patches on the trees and rocks. Commonly used lichens are oakmoss and treemoss thalli.
Protists: Seaweed is commonly used as an essential oil in perfumes.
Synthetic sources: Created through organic synthesis from petroleum distillates or pine resins. They can provide scents which are not found in nature. Synthetic scents are often used as an alternative source of compounds that are not easily obtained from natural sources. Typical examples include musk, orchid scents, linalool and coumarin.

Perfume oils usually contain tens to hundreds of ingredients. The modern perfumes and colognes are made using the fragrance oils developed by fragrance houses. The fragrance oils are then blended with ethyl alcohol and water for a minimum of 14 days and filtered to remove any unwanted particles and then filled into the perfume bottles.

In recent years, celebrities have signed contracts with perfume houses to give their names for the perfumes as a self-promotion campaign. Some of the most popular celebrity-named perfumes include Antonio Banderas (Spirit, Diavolo), David Backham (Instinct), Celine Dion (Celine Dion Notes, Celine Dion Belong), Paris Hilton (Paris Hilton, Just Me), Jennifer Lopez (JLo Glow, Still, Miami Glow, Love At First Glow), Britney Spears (Fantasy, In Control, In Control Curious), Elizabeth Taylor (Passion, White Diamonds, Forever Elizabeth), Maria Sharapova (Maria Sharapova) and many more.