Hi Fiona, Both "free from" and "free of" are often used interchangeably to describe something negative removed from something or someone, resulting in a happier situation. Examples: 1) He dedicated his life to free the world OF hunger. 2) She would like to free herself FROM some of the heavy responsibilities of the organisation and focus on starting a family. However, there are still nuances between OF and FROM: In sentence 1, free OF implies that something negative (such as world hunger) is found WITHIN humanity. It is a problem that has been embedded WITHIN our societies. It is something INTERNAL. In sentence 2, free FROM implies that something negative (such as a set of expectations from others) is imposed on us. We are limited and constrained by some external forces. It is something EXTERNAL. In your sentence, the Earth's electric and magnetic fields affect the side of the Moon which faces the Earth. However, the far side remains unaffected by these EXTERNAL force fields. Therefore, we say that "the far side of the Moon is quiet and free FROM electromagnetic interference." Most readers will still understand what you mean with either "free from" or "free of". Many online dictionaries define both of them together with little distinction. There are, however, cases where only either "from" or "of" is used: Example: When you receive something complimentary, it is given to you FREE OF charge (not FREE FROM CHARGE). I hope this helps.

I would say "free of" although "free from" also sounds fine to me. Actually, I would rewrite the sentence: Since the far side of the moon is quiet and not affected by electromagnetic interference from the earth, it is an excellent place to set up a recording studio. In addition, rents there are quite inexpensive, and you will never be troubled by religious fanatics or traveling salesman knocking on your door. However, if you enjoy gardening, the soil is lacking in basic nutrients and I would urge you to consider setting up your studio on Mars or Venus. You wrote "quite" and I believe you meant "quiet".

free of