Book 'em Danno. 
LOS ANGELES Stage and screen actor James MacArthur, who played "Danno" in the original version of television's "Hawaii Five-0," died Thursday at age 72.
MacArthur's agent, Richard Lewis, said the actor died in Florida of "natural causes," but no direct cause was specified.
In a career that spanned more than four decades, MacArthur was most recognized for his role as Detective Danny "Danno" Williams on "Hawaii Five-0," which aired from 1968 to 1980. Episodes often ended with detective Steve McGarret, the lead character, uttering what became a pop culture catch phrase: "Book 'em, Danno."
Jack Lord, who starred as McGarret, died in 1998.