Why is "Waiting for Godot classified as "Theatre of the Absurd"?

The " Absured drama " or the "Theatre of Absured" gained a
currency as a result of Martin Esllin's book The Theatre Of The Absured published in
1916. Esllin's book deals with a group of plays which incorporates certian beliefs and
use certain methods and as a result of intellectual shorthand, we call Absured drama.
The most surprising thing about this kind of plays is that inspite of their breaking of
the rules they are successful. The major dramatist of the school of Absured, according
to Esllin are Beckett, Adamov, Ionesco and
Genett.

   Esllin make certain important suggestions when
discussing the significance of Absured. According to him, the number of people for whom
God is dead has greatly in present day century. The Theatre Of The Absured is one of the
ways of facing upto a universe that has lost its meaning and
purpose. 

   In Waitin For Godot two characters pass their
time by playing games on the open road. Waiting For Godot this play has been variously
interrupted, even a biographical doucement embodying the relationship between Joyce and
Beckett. Both these writers shows a lack of plot and also in the convectional sense of
character, for character prusemes that personality matters. Just as plot assumes that,
events in time have significance - and both these postulates are questioned in the
plays.