If you haven't checked out Neil deGrasse Tyson's best-selling book The Pluto Files, or heard one of his presentations explaining why Pluto got demoted to dwarf planet--or promoted to king of the Kuiper Belt, depending on how you look at it--you should check it out. The story of all the hate-mail he's received from children is worth it all by itself :)In the meantime, though, here is a short but fascinating introduction by NASA to the history of our scientific understanding of this strange and distant body about which we have been slowly learning since its discovery only 80 years ago.
And if the talk about Percival Lowell and the Mars canals reminded you of Carl Sagan's description of that set of events, why not revisit that fascinating story?
.