The Spy Paramount by E. Phillips Oppenheim

In a life full of surprises Martin Fawley was inclined to doubt whether he had ever received a greater one than when, for the second time during the same day, he was ushered into the presence of General Berati, the most dreaded man in Rome. Gone was the severe high-necked and tight-waisted uniform; gone the iciness of his speech and the cold precision of his words. It was a tolerable imitation of a human being with whom Fawley was confronted--a dark-haired, undersized but sufficiently good-looking man dressed in a suit of apparently English tweeds, stretched at his full length upon the sofa of a comfortable sitting room leading out of his bureau, reading the _New York Herald_ and with something that looked suspiciously like a Scotch whisky and soda by his side. He threw down his paper and welcomed his visitor with a grim cordiality.

"Come in, Major," he invited. "I will offer you a whisky and soda as soon as you tell me exactly whom you found on the other side of that door."