A comprehensive, accessible, and stunningly illustrated introduction to these far-off worlds. The most distant planets in our solar system, Uranus and Neptune were unknown by the ancients--Uranus was discovered in the 1780s and Neptune only in the 1840s. Our discovery and observation of both planets have been hampered by their sheer distance from Earth: there has only been one close encounter, Voyager 2 in the late 1980s. The...