Dario Fo. The author.

Dario Fo is a very skilled man, working in multiple areas of the performance world. He is an actor-playwright, comedian, singer, theatre director, stage designer, songwriter and political campaigner. He won the Nobel Prize in Literature in 1997. 'This marked the international acknowledgement of Fo as a major figure in twentieth-century world theatre. The Swedish Academy praised Fo as a writer who emulates the jesters of the Middle Ages in scourging authority and upholding the dignity of the downtrodden'. (http://en.wikipedia.org/wiki/Dario_Fo)
His work promotes improvisation and 'comprises the recovery of illegitimate forms of theatre, such as those performed by Giullari (medieval strolling players) and, more famously, the ancient Italian style of commedia dell'arte'. (http://en.wikipedia.org/wiki/Dario_Fo) 
His plays are performed world wide and have been translated into 30 different languages. Some of the countries include Argentina, Chile, England, The Netherlands, Poland, Romania, South Africa, South Korea, Spain, Sri Lanka, Sweden and Yugoslavia. Through 1960-1980 his plays made critical reference to assassinations, organised crime, organised religion, racism and war. In recent years his plays have been at the expense of Italy's political leaders such as Silvio Berlusconi. But even more recently the European banks have suffered under the scrutiny of his plays. 

In my opinion Dario Fo's work is still valuable and work like this will always be needed but as society becomes more aware of the actions of the government, police forces and military, the actions taken become more transparent ready for everyone to see. Due to this work like this become less valuable than they were 20-30 years ago when the information was as readily available worldwide.