Michael York stars as King Arthur in this new touring revival of the 1961 musical by Alan Jay Lerner and Frederick Loewe, based on T.H. White’s classic novel The Once and Future King. York, a classically trained Shakespearean actor, brings boyish charm and tragic grandeur to his portrayal of the ruler whose vision of a civilized, law-abiding society is compromised by his pain at the romance between his wife and his greatest knight. As Guenevere and Lancelot, Rachel York and James Barbour deliver powerhouse vocals. Glenn Casale’s staging–with a revised second act that tightens the narrative–melds the story’s elements of romance, fantasy, and moral inquiry better than any production of this work I’ve seen. –Albert Williams a Through 5/13: Tue 2 and 7:30 PM, Wed-Thu 7:30 PM, Fri 8 PM, Sat 2 and 8 PM, Sun 2 and 7:30 PM, LaSalle Bank Theatre, 18 W. Monroe, 312-902-1400, $27.50-$75. C