Book excerpt: IF your love life, married or otherwise, is fulfilling and there is every evidence it will continue that way -- congratulations. But IF your romantic history reads like a Greek tragedy, or all the pages are blank, you may be holding the key that will open the way to a whole new beginning. Of course, there are shelves full of books on this subject. So what's inside this volume you won't find between other covers? Be forewarned, you won't encounter much conventional wisdom here. The author will take you down a road less traveled. Her prescriptions may justify the title of 'radical,' certainly challenging, definitely provocative but ultimately encouraging. Lasting and mutually supportive relationships are not Heaven-sent. They depend on certain key interpersonal attitudes and actions you'll find within. Whether you're a couple or single, man or woman, Are You Fit to Love? is "A lifeline worth grabbing." Read and reap. Book jacket.