My father often spoke about his life long quest to explore what love is. He tried defining it in ways that made sense, that was logical even though love is closer to a metaphysical concept. His search began before my birth and continues now through me 7 years after his passing. He spoke about Erik Fromme's writings, about the difference between love and libido, on how he still loved my mother after their separation and divorce. I learned a great deal from my father about the nature of love and it's power to nurture and redeem and help others.
There is need by me to utilize the head when viewing the heart. I believe many of us do this. The head is logic and the heart is emotions and passion and the center of love.
I'll start with this:
"When the happiness of another person becomes as essential to yourself as your own, then the state of love exisits."- Robert Heinlein