This two songs setting up a mini-suite come from "In Search of The Lost Chord" and are a fascinating specimen of what we seldom call proto-progressive rock. The first part of "House of Four Doors" has a tricky and diversified plot, lining up the main theme and some excellent instrumental sections, where Mellotron, flute and other classical instruments rule. After all, this unusual structure that perfectly matches with the quest and exploration concept of the LP.
This unpredictable work was the third studio album by TMB.
The vocal harmonies are another winning point, especially in the second part, acting like a choral coda, that another long song, "Legend of A Mind", divides from the first and longest part. This song has the plain melodies of the Sixties but also the highly sophisticated care for each detail defining the style of so many prog bands from the Seventies. Once again, The Moody Blues were simply forward.