Rules for the Playfair Cryptograms

To aid you in cracking the Playfair cryptograms this month, I have included (as I did last month) a chapter from Helen Fouche Gaines's outstanding work, Cryptanalysis:  A Study of Ciphers and Their Solution, first published in 1939.  Gaines's explanation is, in my opinion, still one of the best on this subject.    


Neglect not the "crib"!


In these cryptograms, I've deliberately constructed both the message and the keyword to be accessible by "cribs."  These are useful, as confirmed by several messages by solvers via private channel indicating they have broken ciphers almost entirely by guessing the right "crib."


***Take me to the Playfair cryptograms!***