Actually i need some information regarding the popularity of Satire during 18th century. What were the major reasons of its popularity and who were the major satirests of that era. Thanks,

The 18th century was a period of intellectual transformation and of enlightenment. Newer ideas were emerging regarding monarchy, the social structure, and religion. The purpose of satire is to reveal the flaws in established manners and ways of living. Satire also seeks to subvert the existing order of things and especially to discredit political leaders and the ruling class.
The two most prominent satirists in English during the 18th century were Jonathan Swift and Alexander Pope. Swift's Gulliver's Travels is a satire on both the political scene in Britain and, more importantly in Book IV, mankind in general.
In the final section of Gulliver's Travels, Swift has his hero land in a world where human beings have become degraded, animal-like savages, the Yahoos, while intelligent horses, the Houyhnhnms, are the rulers. (It's interesting that the name by which the latter are known is a representation of the sound that horses typically make.) Two centuries later, this scenario was recast by the French writer Pierre Boulle in Planet of the Apes and the countless movies it spawned. By portraying humans as Yahoos, Swift is basically caricaturing the worst sides of human behavior—dirtiness, selfishness, and greed. He also is making a point about the contrast between man and the animal kingdom in the real world, showing that animals, unlike humans, are benign, that they don't make war or kill for sport, and so on.
Swift is aware that his satiric portrayal is an exaggeration, but it is nonetheless a meaningful one. When Gulliver is rescued, the most impressive thing is the kindness with which he's treated by the Portuguese ship captain, belying the totally negative view of humans Gulliver has now adopted after his stay in the realm of the Houyhnhnms and Yahoos. But the impression Swift has given of the worst side of humanity lingers in the mind of the reader.
Swift uses an even more trenchant type of satire in A Modest Proposal, in which he skewers the English attitude toward Ireland. Swift has the "author" of this work suggest, apparently in all seriousness, that the English "eat" the Irish in order to solve the economic problems of Ireland. The bigotry and cruelty toward the Irish by the ruling class in England are thus satirized by Swift's presenting them in an extreme and caricatured form, namely, as cannibals.
Alexander Pope was less focused on holding the general behavior of mankind up to ridicule than on attacking his enemies in the literary world, such as the playwright Colley Cibber. Pope, however, is best known today for The Rape of the Lock, a comparatively gentle work in which he pokes fun at the vanity of men and women in upper-class English society. It is a "mock-heroic" epic in which Pope ironically uses language borrowed from Homer and Virgil to describe trivial and silly events and actions, making his characters look even more ridiculous than they do in real life.
The most important satirist of the period in France, and perhaps in Europe as a whole, was Voltaire. In Candide, Voltaire takes on religion, something the English writers of the period didn't do, at least not so openly. Voltaire presents a parable of recent European history, depicting wars and natural disasters and using these events to ridicule the established monarchical order and the religious and philosophical thinking that could attribute all of this to the workings of a benign God and that could describe this as "the best of all possible worlds."
Both the English writers and Voltaire (and his fellow philosophes in France) saw the injustice and hypocrisy in the whole "system" by which Europe was governed at that time, and in the behavior and attitude of human beings in general. As stated, they lived in a period, later called the Enlightenment, when established ideas were openly and forcefully questioned, and when it became the goal of intellectuals to bring about a transformation in the European world, leading to the American and French revolutions. Satire was an effective method of accomplishing this goal.