As Drew notes, Brian Lamb is a major media figure and I want to follow Drew in congratulating him on his retirement, albeit for different reasons.
Drew and others appreciate the book segments on C-Span. I found them to be the weakest link, driven by narrative-based pop history and queries from that same pop-history standpoint. The recurring problem with C-Span interviews of authors is that each author was enshrined as an expert. This is opposite to Feynman's formula that the esence of science is to treat expertise as ignorance.
In one of his Jazz Casual TV shows, ETV's Ralph Gleason queried Count Basie on the lines of, Do you think jazz will ever lose its blues basis? The possibility worried Gleason to death and is indicative of that cultural ultraconservatism that attracts people to ETV (in that day), PBS (nowadays), and NPR. It's the same cultural rigidity that reduces classical radio stations to what Zappa called "top 40 hits" and other safe bets.
The common theme here is deference to authority. The good part of C-Span showed us the face of authority as it is. The worst part of it deferred to this or that jackass author-authority. Brian Lamb had this blind spot.
In the end though, the best part of one C-Span channel was worth more than all the ETVs, PBSs, and NPRs put together over the last 50 years. In that I thank Drew for reminding me to tip my hat to Brian Lamb.