August Strindberg's importance for the development of modern drama is fundamental and undeniable. Few modern playwrights have been unaffected by him. Eugene O’Neill, in 1924, already considered him “the most modern of moderns, the greatest interpreter in the theatre of the characteristic spiritual conflicts which constitute the drama – the blood! – of our lives today.” Some forty years later, Martin Lamm called him “the boldest [-] experimenter in modern drama.” For Ingmar Bergman, Strindberg was a lifelong companion: “I tried to write like him, dialogues, scenes, everything. I felt his vitality, his anger inside me.”

Like most successful modern dramatists, Strindberg wrote his plays for two kinds of recipients – readers and spectators. All his plays were published either before or in a couple of cases about the same time as they were staged. The time lapse between publication and production could sometimes be considerable (see the play list, page 174-179). This means that, unlike those dramatists today who do not publish their plays until these have proved stageworthy, that is, after they have been tested in rehearsals or productions, Strindberg, as he himself put it, had once and for all written what he had written. This was at least true in the sense that although most of the plays were written very quickly, he made very few changes in the proofs.

August Falck, actor, manager and director at Strindberg's Intimate Theatre, has described how he once, in the spring of 1907, was an eyewitness to Strindberg's way of writing: