Millions of words have been written on the true nature of love, but few are as succinct as in this book. This seminal inspirational work divides 'love' into four categories: Affection, Friendship, Eros and Charity. The first three come naturally, but without Charity, C.S. Lewis shows how all love can become distorted, bitter and even dangerous.

Of the four C.S. Lewis books I've just bought, this is the one I'm least looking forward to reading. Just because love is such a personal thing, I don't know if anyone (however skilled) can really rationalise it. Maybe I'm wrong.