Beckett Briefs, the rubric for three short plays by Samuel Beckett at the Irish Repertory Theatre, provides a rare look at works by the dramatist whose Waiting for Godot has overshadowed all theater since the mid-20th-century. The progression of plays devised by director Ciarán Hinds moves from the slightest, Not I, featuring only a mouth speaking, to Play, in which only three heads appear, to the longest, and most fruitfully theatrical, Krapp’s Last Tape, featuring Oscar winner F. Murray Abraham, head to toe. All three works are suffused with regrets about or outrage at the setbacks, blunders, jealousy, and dishonesty in the characters’ lives.