C.S. Lewis

Like fresh baked cookies, you cannot have just one -- you must read The Magician's Nephew to be there at the birth of Narnia and the start of the adventures; then after LW&W read Prince Caspian right away and probably Dawn Treader before jumping to The Last Battle. Then, of course, you might as well read all the rest.

If you could have only one, this edition would be the one to have: 1950 1st edition, $22,000 and it's on your bookshelf!