NABOKV-L discussion

This  message  was originally  submitted  by  alainfchamplain@GMAIL.COM 

Who did/do you think Gerald Emerald was referring to when he said “I guess
Mr. Shade has already left with the Great Beaver," in the Foreword?

I always thought the joke was obvious, but I've come across several
theories involving Castor and Pollux, Castro, Shakespearean armor — none of
which have mentioned the heart of the bit.

At this risk of stating the obvious: