• Willie Nelson

As he approaches his 78th birthday on April 30, Willie Nelson seems to have lost none of his enthusiasm for performing (to say nothing of his enthusiasm for weed). He returns to Chicago on Friday for a concert at the Chicago Theatre.

Though he was once a key figure in the Texas outlaw-country movement, along with Waylon Jennings, he was mainstreamed long ago and became a sort of non-denominational American treasure—on his 1978 classic Stardust (Columbia), he interpreted some of America’s most enduring prewar popular music, honoring Gershwin, Carmichael, and Berlin (rather than Williams, Wills, and Rodgers). In the decades since, Nelson has nonchalantly (and sometimes somnambulantly) tried on many styles and genres for size, from reggae to jazz to blues. (I bet he’s got a samba album in him somewhere.) His voice is the epitome of easygoing, but his recorded output has been so erratic that you could be forgiven for imagining he’s just generating product to meet some contractual obligation. At the same time, no matter what he tackles, it always sounds like Willie Nelson music.