I've read the book Between Silk and Cyanide by Leo Marks and wrote the following comment on Goodreads:

Between Silk and Cyanide was a wonderful recommendation I received and it really paid off. When you think about cryptography during WWII the names that come to mind are Bletchley Park and Alan Turing, but Leo Marks did a fantastic job too. He describes his battle with the bureaucracy to provide better codes to the agents on the field in a very humorous tone, also he writes very well and the book is very agreeable to read.

My only regret is not having discovered this book while my grandpa was still alive a few years ago. He worked for 40 years as a WT operator and there are several morse code issues the book discuss and he would love to talk about it, in fact I learned morse from him. The last time we met he showed me a poem he wrote to his wife (my grandma) using morse code.

Even if you are not into cryptography you will enjoy this book. However if the cryptography bug infects you I'd suggest other two good books one non-fiction The Code Book: The Science of Secrecy from Ancient Egypt to Quantum Cryptography from Simon Singh, and other a spy novel from Robert Littellwhich has as main part of the plot the "Baconian theory of Shakespeare authorship" and the Bacon's Cipher: The Amateur.

I'm grateful to the author of Arriving at Amen: Seven Catholic Prayers That Even I Can Offer , Ms. Leah Libresco, for the recommendation of Between Silk and Cyanide.

P.S.: (have fun and crack, not so hard...!)

But maybe it's hard, so a guess on how to crack it.

Step 1) Record the Morse transmission on Audacity or other program you like.

Step 2) Optional: Clean the Background noise showing a noise profile to Audacity and then filtering out the noise.

Step 3) Look at the wave

As you might guess the long wave is a dash and the short one a point.

Knowing this and the morse code, you can easily decode the morse and then apply some very-easy "crypto" to get the plaintext. It has to do with something in the review.