Read the following passage. Then, answer the question that follows.
This year marked the twenty-seventh year of the annual Chicago Blues Festival.
As in previous years, the music festival took place in Chicago's Grant Park.
Performers, young and old, shared their variations on the blues with large
audiences against a backdrop of skyscrapers. Multiple stages were set up
throughout the park, in addition to a large selection of food and beverage
vendors. As this year would have been the 100th birthday of blues legend Howlin'
Wolf, the festival was dedicated to him. Though Howlin' Wolf was originally from
Mississippi, his recording career was spent in Chicago. Alongside other legends
such as Muddy Waters, Willie Dixon, and Sonny Boy Williamson, Wolf is credited
with developing the unique blues style that came to be known as Chicago Blues.
What is the author's purpose in writing this article?