Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Well balanced and engaging modern cultural history of Mars

I bought this book on a whim after getting interested in Mars colonization after reading Kim Stanley Robinson's Mars trilogy, to which Dr. Morton's book is an excellent non-fiction counterpoint. Not only does he set forth a well-spoken, engaging exposition of the 20th century's cultural and scientific history of Mars, he balances this with a keen sense of the limitations of human knowledge, telling his story in the context of real, live human figures at the forefront of Mars exploration.The central theme, of maps and how they relate to place - and furthermore, how we relate to those maps and places - sets off an easily read story of what Mars has meant to recent society, how scientists have shaped that understanding, and how that understanding is both formed and limited by our extended observers, the robot orbiters and landers that we've sent to our red neighbor.Highly recommended reading both for historical and cultural interest.