In my interest in classic films, I don't know how this one escaped me. If you've seen The Mirror Has Two Faces with Barbara Streisand, that film was a remake of Without Love. I like both films equally and I like them both quite a lot.
In this one, Tracy plays a brilliant scientist who has been burned in love. Hepburn plays a widow who has experienced love at it's best. They have different reasons for choosing to marry as only friends...
That's all I'm telling you.. It has it's Hollywood wierdnesses as far as the script goes. There are a few awkward moments and it goes a little long in spots.. but, it's a pretty fantastic little film all in all.
BTW... It's fun to see Lucy in this too. She's very pretty.