For a country so fixated on uniform policy and mass production, could a forgotten little phrasebook be so important?
It would have been everywhere, were it not just another contingency plan out of hundreds of bizarre scenarios. We would have heard about it.
After what the Russians went through between 1941-1945, I'm sure Stalin wanted and ordered that all memory of his 1939-1941 alliance with Hitler be erased.
In 1940, Germany and Russia were allies. A phrasebook containing English phraseology directed at an English speaking military and civilian population means Stalin was considering taking part in operation Sea Lion alongside his Nazi allies.
The author is just trying his best to keep that from getting out.
Some on this thread advance theories that the book may have been prepared for possible use in Skandanavia or in Central Asia where British Colonies existed. The Skandanavian theory cannot explain the need for phraseology directed at English speaking civilians and can therefore be eliminated.
The theory about Stalin making a move in South Central Asia for a warm water port has some merit as India, Pakistan and Iran were all British possessions or colonies and some portion of the civilian population might speak English. However, why didn't the book include phrases in local languages such as Farsi, Urdu, Pashtun or Hindi as one would expect when confronting a mixed language allied force/population?
The exclusively English nature of the books points to only one explanation. Stalin was planning to assist his Nazi allies in the invasion of Britian. That is what the author tried so desperately to avoid mentioning.