The previous reveiwer has got it spot on. This is an intelligent music show where one professional musician interviews others.
The first episode I watched on recieving the set was the Diana Krall one, who is interviewed by Elton John rather than Elvis Costello. She talked movingly about her friendship with Oscar Peterson, in the last five years of his life, as well as her love for many kinds of music. She also played some swinging Jazz Piano. Elton interviewed her from the side of the Piano loving every moment of it.
Elvis Costello may have started as part of the post punk new wave movement, but has matured into a musician who can do it all. In general he gets more out of the guests than any normal talk-show host would. As well as interviews there are also some fabulous musical collaborations. Watching the Elton John interview last night it was amazing to see Allen Toussaint on Hammond organ and James Burton on guitar in the backing band as Elvis and Elton sang a David Ackles song.
Other guests include James Taylor, Herbie Hancock, Pat Methany, Tony Bennett, Rufus Wainwright and Ex-President Bill Clinton.
This is on 5 DVD's with a total running time of 650 minutes, so although the price may look expensive it is actually good value for money. I can't recommend it highly enough.