Essential non-fiction please?

i love to read, i read all the time, but recently i realised that instead of reading all these fiction books i could be reading non-fiction and be furthering my intellect. if anyone has any non-fiction books they can recommend, on any subject, i mean anything, psychology, business, history, art, anything that is just a really good read, and something i can learn from, i'll be incredibly grateful. i'm 15, but i read at a pretty decent level.