Morse Code Books

“On a distant hilltop, twinkling like an early evening star, a white light was flashing.
Blouse lowered his telescope. ‘They're repeating "CQ",’ he said. ‘And I believe those longer pauses are when they're aiming their tube in different directions. They're looking for their spies. "Seek You", see? Private Igor?’
‘Thur?’
‘You know how that tube works, don't you?’
‘Oh, yeth, thur. You jutht light a flare in the box, and then it'th just point and click.’
‘You're not going to answer it, are you, sir?’ said Jackrum, horrified.
‘I am indeed, sergeant,’ said Blouse briskly. ‘Private Carborundum, please assemble the tube. Manickle, please bring the lantern. I shall need to read the code book.’
‘But that'll give away our position!’ said Jackrum.
‘No, sergeant, because although this term may be unfamiliar to you I intend to what we call "lie",’ said Blouse. ‘Igor, I'm sure you have some scissors, although I'd rather you didn't attempt to repeat the word.’
‘I have thome of the appliantheth you mention, thur,’ said Igorina stiffly.”
― Terry Pratchett, Monstrous Regiment