Johnny Mathis’s sixth album was, on the face of it, simply another in the series of Mitch Miller/Al Ham-produced and Percy Faith-arranged albums that made his late 1950s name. But it was of course also a Christmas album and over time it became one of the landmarks in the genre, blending pristine orchestral pop and Mathis’s elegant voice beautifully, especially on the melancholy songs. A mix of mid-20th century holiday standards and older carols, song for song Merry Christmas almost literally sparkles, especially on “Winter Wonderland” and “Sleigh Ride.”