Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Their Best Effort

In my opinion, this is the Moody Blues' best studio album. Although they start off with a very unusual, mostly instrumental/special effects "song" which appears to trace the history of humankind, from there on it is pure Moody Blues. The songs are lavish, thought-provoking, and utterly entertaining. The album has a certain "Middle Earth" quality to it which seems to transport the listener to another time and another place ... where things are difficult, but both hopeful and tolerable. I've listened to this album well over a hundred times since 1971, and it is probably my all time favorite of all genres.