Turkish bath or hammam is the Turkish variant of the Roman bath, steambath, sauna, or Russian banya, distinguished by a focus on water, as distinct from ambient steam.
In Western Europe, the “Turkish bath” as a method of cleansing and relaxation became popular during the Victorian era. The process involved in taking a Turkish bath is similar to that of a sauna, but is more closely related toancient Greek and ancient Roman bathing practices.
The Turkish bath starts with relaxation in a room (known as the warm room) that is heated by a continuous flow of hot, dry air, allowing the bather to perspire freely. Bathers may then move to an even hotter room (known as thehot room) before they wash in cold water. After performing a full body wash and receiving a massage, bathers finally retire to the cooling-room for a period of relaxation
The difference between the Islamic hammam and the Victorian Turkish bath is the air. The hot air in the Victorian Turkish bath is dry; in the Islamic hammam the air is often steamy. The bather in a Victorian Turkish bath will often take a plunge in a cold pool after the hot rooms; the Islamic hammam usually does not have a pool unless the water is flowing from a spring. In the Islamic hammams the bathers splash themselves with cold water.
The Victorian Turkish bath was described by Dr Johann Ludwig Wilhelm Thudichum[3] in a lecture to the Royal Society of Medicine given in 1861, one year after the first Victorian Turkish bath was opened in London:
‘The discovery that was lost and has been found again, is this, in the fewest possible words: The application of hot air to the human body. It is not wet air, nor moist air, nor vapoury air; it is not vapour in any shape or form whatever. It is an immersion of the whole body in hot common air.

The hamam combines the functionality and the structural elements of its predecessors in Anatolia, the Roman thermae and baths, with the Central Asian Turkic tradition of steam bathing, ritual cleansing and respect of water [12]It is also known that Arabs built versions of the Greek-Roman baths that they encountered following their conquest of Alexandria in 641. From the tenth century, Turkish kingdoms began to proliferate in Anatolia in lands conquered from the Byzantine Greeks, leading eventually to the complete conquest of the remnants of the old empire in the fifteenth century. During those centuries of war, peace, alliance, trade, and competition, the two cultures – Hellenized Roman and Anatolian Turkish – had tremendous influence on each other. Moving beyond the re-use of the Greek baths (for example Byzantine Bath (Thessaloniki)) in their new lands, new bath were constructed as annex buildings of mosques, the complexes of which were community center as well as houses of worship.

The Ottomans in particular became prolific patrons of baths, building a number of ambitious structures, particular in Constantinople after it became their capital in 1453.[13] The monumental baths designed by Renaissance Ottoman architect Mimar Sinan (1489–1588), such as the stand alone 1584 “Çemberlitaş Hamamı”, the bath in the complex of the 1558 Süleymaniye Mosque (both in Constantinople) and the bath of the Selimiye Mosque inEdirne were particularly influential.
Like its Roman predecessor a typical hamam consists of three basic, interconnected rooms: the sıcaklık (or hararet -caldarium), which is the hot room; the warm room (tepidarium), which is the intermediate room; and thesoğukluk, which is the cool room (frigidarium). The main evolutionary change between Roman baths and Turkish baths concerns the cool room. The Roman frigidarium included a quite cold water pool in which patrons would immerse themselves before moving on to the warmer rooms. Medieval Muslim customs put a high priority on cleanliness, but favored running water to immersion baths, so the cold water pool was dispensed with. Also the sequence of rooms was revised so that people generally used the cool room after the warmer rooms and massages, rather than before. Whereas the Romans used it as preparation, the Ottomans used it for refreshment (drinks and snacks are served) and recovery.

The sıcaklık usually has a large dome decorated with small glass windows that create a half-light; it also contains a large marble stone called göbek taşı (tummy stone) at the center that the customers lie on, and niches with fountains in the corners. This room is for soaking up steam and getting scrub massages. The warm room is used for washing up with soap and water and the soğukluk is to relax, dress up, have a refreshing drink, sometimes tea, and, where available, a nap in a private cubicle after the massage. A few of the hamams in Istanbul also contain mikvehs, ritual cleansing baths for Jewish women.
The hamam, like its precursors, is not exclusive to men. Hamam complexes usually contain separate quarters for men and women; or males and females are admitted at separate times. Because they were social centers as well as baths, hamams became numerous during the time of the Ottoman Empire and were built in almost every Ottoman city. On many occasions they became places of entertainment (e.g. dancing and food, especially in the women’s quarters) and ceremonies, such as before weddings, high-holidays, celebrating newborns, beauty trips.
Several accessories from Roman times survive in modern hamams, such as the peştemal (a special cloth of silk and/or cotton to cover the body, like a pareo), nalın (wooden clogs that prevent slipping on the wet floor, or mother-of-pearl), kese (a rough mitt for massage), and sometimes jewel boxes, gilded soap boxes, mirrors, henna bowls, and perfume bottles. Traditionally, the masseurs in the baths, tellak in Turkish, were young men who helped wash clients by soaping and scrubbing their bodies.
After the defeat and dismemberment of the Ottoman army in the early twentieth century, the role of tellak boys was filled by adult attendants.

Source: http://en.wikipedia.org/wiki/Turkish_bath