well it appears I had it wrong when I suggested that Berkeley has been ticked off at Sayers for the way she handled his detecting creation, Roger Sheringham! thank you Martin Edwards, in your Forward to this collection, for refreshing my memory with the fact that it was Sayers who was not at all pleased with the way Berkeley parodied Lord Peter Wimsey; I knew (from reading The Golden Age of Murder) that someone was pissed off at somebody, but, as a few cartoon characters have been known to lament, "I had the silly thing in reverse!".
meanwhile, I tackled Edwards' intro, and a Preface by Agatha Christie, which it seems was culled from a later time, 1945, and inserted into the launch of this edition, because it sorta fits. fair enough--an interesting summary of her fellow Detection Members and their efforts, before humbly chatting about her main man, Poirot. doorkeepers dealt with, I am 19 pages into a story called 'Death at Hursley Lodge' by John Rhode. there is a map! luckily, I can actually make things out on the map!