Love is one of the hardest words to say and one of the easiest to hear, and explaining it lies somewhere in between. One can "love" a book, a pet, or another person. Seemingly all of those types of love are very different, however I would like to propose that they are indeed extremely similar - and that love itself is a universal feeling no matter the subject.
Reading a book one loves creates a connection with the story that relates to your own life. Understanding the author or hero brings us joy and comfort, knowing someone else out there feels the same way we do. When one loves a pet, they love the connection that animal displays to its owner, even if it's just anthropomorphic. Fetching the morning paper, licking your face, or laying by your side are all signs of devotion. The animal most likely associates you as someone that provides food and security, thus a symbiotic relationship forms between the two. Most of us realize this but don't mind - as long as it feels good.
When one loves another human being, it becomes much more complicated. You can love a wife, a mother, or a friend with seemingly different levels of emotion. But is it actually different? Our developed brains use reason to ask questions and look for answers. We have the ability to look for meaning in the Universe, but ultimately we fail, which leaves us frustrated, confused, and alone. However, we are social creatures and therefore we find solace and comfort in two forms - through the love of others and through the creative arts. We look to others (a wife, a mother, a friend, or an author/artist) to trust in and rely on, creating a connection or feeling of completeness.
We search for love in its many forms so as not to be alone in the meaningless, absurdity of it all. Take the Universe for instance - its the Mother of all mothers and the most beautiful, grandest creation ever. I can barely fathom what I know about it, and realize there are so many things I'm not even aware that exist within it! Therefore I love the very thing that makes me feel alone in the first place. A Catch-22 of sorts, which by the way, is a book I love.