Shakespeare's greatest contribution to literature would probably be the variety of material that he produced during his lifetime. He wrote histories, such as Julius Caesar. He wrote love stories, most famously Romeo and Juliet. He also wrote comedies such as The Taming of the Shrew. His poetry is often quoted as well as lines from his plays.  He single-handedly invented new words for the English language such as "assassination." His characters are quite believable and have been analyzed by critics ever since the plays were first produced. Shakespeare wrote at a time when plays were quite popular in England and he gave the viewing public what they wanted, whether they were the rich with good views or groundlings who could not afford good seats. Even in today's entertainment industry it is hard to create something that appeals to such a large group of people. Shakespeare's work is timeless and has been adapted to stage, screen, and even radio.

Why is Shakespeare the greatest writer of all time?

The first point one should make is that there is absolutely no way to prove this claim. There have been many great and influential writers across a wide range of periods and cultures, and there is really no way to measure who is the "greatest." To say Shakespeare is somehow objectively "greater" than Homer, Basho, Lady Murasaki Shikibu, Dante, Sophocles, Tolstoy, or the anonymous author of the Epic of Sundiata is to make a claim that one cannot really support without being narrowly ethnocentric.

What one can actually claim is that Shakespeare is one of the most innovative and influential figures in English literature. He was important for the development of two genres, poetry and drama. In drama, he was a pioneer of the "mixed" drama which blended comic and tragic elements, often by the introduction of "rustics" or "mechanicals" into a drama otherwise dealing with the travails of noble characters. He also is generally credited with inventing the device of the quarreling lovers (such as Beatrice and Benedict in Much Ado About Nothing). Many of Shakespeare's phrases have become part of the common currency of the English language. He was also quite important for his contributions to the evolution of the English sonnet. 

Why is Shakespeare so great?

There are a lot of reasons why Shakespeare is great. Here are a few for you to consider:

• Shakespeare wrote 37 plays and many poems. Over the course of his life, that amounts to a staggering 884,647 words, according to the BBC.
• Shakespeare invented over 1,700 words which are still in use today. Every time you use the word 'fashionable,' 'eyeball,' gossip,' or 'puking,' you can thank Shakespeare for inventing it.
• Shakespeare was an actor as well as a writer and performed in some of Elizabethan England's greatest venues, including the famous Globe Theatre.
• Shakespeare's plays and poems are so good that they are still in print today and have been translated into many different languages. Part of his appeal comes from the fact that he wrote about timeless issues, like love, death, and ambition.