Kerning is the art of spacing individual characters in a word so that they sit in correct relationship to one another, creating a subtle harmony and rhythm. In the increasingly fast-paced world of graphic design kerning is often underrated and forgotten. While it is one of the hardest arts for a designer to master, it can be involving and interesting - and yes, even fascinating.
Above all, kerning feels like a true craft. Explaining it to someone who's not a designer often elicits raised eyebrows and cries of "Why bother?". But it's the subtleties in typesetting that distinguish competent work from true typographic beauty. That said, to be truly great at kerning takes years of practice. There are some really simple things that will help you no end and get you started down the path of the obsessive kerner.