Before the talk on Mackenzie King, Churchill and Roosevelt you may be interested in reading about Churchill in Britain's "Darkest hour".  Eric Larson has written a fine book called  "The Splendid and the Vile" which covers the year that Britain teetered on the brink.

Here is a review https://www.goodreads.com/book/show/51187948-the-splendid-and-the-vile