World War II Behind Closed Doors: Stalin, Nazis, and the West Book

I'm rating this so highly because it answered important questions regarding Poland and WWII at exactly the right time. I suspect the treatment may be simplified or delivered in a simplistic way given that it was produced as a series of documentaries.

It is astonishing that the British were so slow to defend themselves in real terms under Churchill's leadership, instead portrayed as incessantly resisting Stalin's demands for a Second Front, despite Roosevelt's much earlier commitment to send more troops to the continent than the UK ever did.

I've read other reader reviews which suggest that the book is overly apologetic regarding Churchill's position, but my impression was exactly the opposite, to the degree that I thought there might be some overt bias by the author, based potentially on what I'm told is a Welsh surname.

The book dwells altogether too much on stated positions and summary non-binding agreements, such as Potsdam, in order to explain history. It is less successful when it tries to describe the motives of the key players. Since Stalin was indeed so untrustworthy, why did he forfeit so much territory the Russians won with so much hardship going into Germany?

Still, the writer's sometimes outright contempt for the British position seems ever more justified the more one reads about the events leading up to WWII.