How to divide Harold Pinter's plays?Which groups can I divide his plays into?

Pinter's plays written in the late 1950s and in the 1960s
such as The Room (1957), The Birthday Party
(1958), The Caretaker (1960) are influenced by the
theatre of the absurd and by Pinter's reading of Kafka and Beckett. Although the
working-class settings are recreated with an apparent attetion to
details, Pinter's plays from these two decades are not naturalistic. Their purpose is to
comment on the absurdity of human lives and on the alienation of modern man, caught in
his inability to achieve meaningful communications with his fellow human beings. These
are sometimes grouped as "menace comedies" as the existence of the main characters is
threatened by some entity or person outside their
group.

Pinter's production of the 1970s, 1980s and
1990s such as One for the Road (1984), Mountain Language
(1988), Ashes to Ashes (1996) are more overtly political
and reflect the playwright's growing militancy.