CBS owes a great deal of its success over the past 15 years to the original "CSI," which is why it's getting the grand farewell treatment its spin-offs didn't. "CSI: Crime Scene Investigation" has been canceled, but there will be a two-hour finale special on September 27, bringing back original castmembers including William Petersen and Marg Helgenberger.

The franchise will continue with the renewal of "CSI: Cyber," which will add Ted Danson (who has fronted "CSI" Coke Classic in its final years) to its cast.

At CBS' annual upfronts press breakfast, scheduling chief Kelly Kahl called the original "CSI" a show that was "easy to take for granted, easy to forget. This is one of the strongest, longest-running dramas in TV history, and very important to us as a network. It was one of the shows that really helped reverse our fortunes and point us in a very positive direction. So I'm very happy that we can send it off in the right way."

Alan Sepinwall has been reviewing television since the mid-'90s, first for Tony Soprano's hometown paper, The Star-Ledger, and now for HitFix. His new book, "TV (The Book)" about the 100 greatest shows of all time, is available now. He can be reached at