"Christmas Time Is Here" is a popular Christmas standard written by Lee Mendelson and Vince Guaraldi for the 1965 television special A Charlie Brown Christmas, one of the first animated Christmas specials produced for network television in the United States.
Two versions were included on the album A Charlie Brown Christmas: an instrumental version by the Vince Guaraldi Trio and a vocal version by choristers from St. Paul's Episcopal Church in San Rafael, California who had previously performed with Guaraldi on At Grace Cathedral (1965).
The beautiful tenor sax playing is provided by good buddy, Matt Demerritt. [http://www.mattdemerritt.com/]
Here I explain what a 'secondary dominant' is and what scales to deploy in various secondary dominant situations.
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https://www.youtube.com/watch?v=V5yksRsz5fE