Betsy Morgan and Lewis Cleale age gracefully in Signature’s “Giant”

Let’s get one thing out of the way early – Signature Theatre’s Giant is worth the four (yes, four) hour investment.

The new musical from Michael John LaChiusa was gaining notoriety for its epic length even before it opened (Signature itself took the tactic of joking about it in its marketing materials, calling it a “Texas-sized musical”). But the work, based on the Edna Ferber novel (and resulting film) of the same name, is much more striking not for how extensive it is, but for how smart and adult it proves to be.

How should a woman cope with the sexual rejection she feels from her husband as she ages? How do two adults who have managed to grow old together without really knowing each other find common ground, despite differing values? What’s the appropriate role for grief in a man’s life? They’re big ideas and they receive sensitive, multi-dimensional treatment, particularly when set to song in LaChuisa’s hands.