As I mentioned before, this season will focus on alternate history and the guys did not disappoint with their first episode. I am listening to it now as I read this post and they have begun the new series by taking a look at Kim Stanley Robinson's The Years of Rice and Salt.
Nominee for the 2003 Hugo for best novel and the 2002 BSFA Award for best novel, there is no argument that the novel is an important work of AH. Our hosts take a scholarly look at the novel and alternate history in general, with some laughs thrown in to keep you entertained. Go check it out.