“What Child Is This” demonstrates that Bill Champlin’s greatest contribution to Chicago was his arrangement acumen. This statement in no way diminishes Champlin’s vocal chops or his keyboard and organ talent. There are also a few great examples of Champlin’s excellent fretwork with Chicago.

Chicago XXV: The Christmas Album—and its expanded successor, What’s It Gonna Be, Santa?—showcases vocal stacks to die for. Indeed, the vocal savant Champlin was able to blend with Jason Scheff in a way that, in many cases, surpassed his work with Peter Cetera. On this classic Christmas chestnut, Champlin’s vocal harmonies are among his best work. The arrangement builds as the song progresses, supporting the passionate lead vocal beautifully.

Producer Roy Bittan achieved something few other producers have with the band: balancing all the elements to move them forward while retaining the unique Chicago sound. Lee Loughnane’s muted trumpet, Tris Imboden’s intuitive drumming (along with an understated drum-machine program), and Keith Howland’s melodic electric guitar wrap the perfect rock, jazz, and R&B elements in a bow.

The Bittan-produced songs stand in stark contrast to the Phil Ramone-produced tracks from What’s It Gonna Be, Santa? and leave me wondering why Bittan didn’t get the opportunity to produce a full album of original Chicago material.