Bertolt Brecht's The Caucasian Chalk Circle ranks with the greatest plays ever written. It's based on an old legend about a wise judge who has to decide which of two mothers a child belongs to, and it has a tender quality that blends with the acerbic honesty you expect from Brecht. The Winter's Tale is the only other play I know with as deep a feeling for dialectic change and the hope it makes possible. With any kind of production, it should be a good play not to miss. Opens tonight, 7:30 p.m. at the Loeb Ex.

Dark of the Moon, by Howard Richardson and William Berney, purports to be a folk drama about Tennessean witches. This witch boy wants to be a real boy but the girl he's in love with breaks her supernatural contract and he has to go back to witchery. Word is that she, on the other hand, got a job taking dictation at the White House, Tonight till Saturday, 8 p.m. in the Leverett Old Library.

Harlem in the Evening is from Langston Hughes, and there's a review of it on page 2. Tonight till Saturday at the Loeb, 8 p.m.

Hardesty Park is by William McCleery, an apparently somewhat lightweight Broadway playwright who had some successes in the '40s and is hitting the comeback trail after a stint teaching at Princeton. Tonight till Saturday at Adams House, 8:30 p.m.

Keep Your Pantheon is a German-expressionist investigation into the theories of R.D. Laing, and the schizophrenia inherent in strivings for spiritual rebirth--"Changing the pantheon," as the somewhat clumsy translation has it. At the Hasty Pudding Club.