[fauigerzigerk]

>Where it can become confusing is when money leaves you or comes in from an external source. There are still two entries, but one entry is in one party's books and the other entry is the other's. For example, I get a paycheque and I enter my income in a little book with green paper and DB/CR columns. At the same time, my employer has entered an expense in their book. Double entries.

I agree with your first two paragraphs but not with this last one. When money leaves you or comes in from an external source, there is always some proxy account for that external party in your own books. And the whole situation is mirrored in the accounting system of the external party (unless they are a consumer). Each party records two entries.

[bregma]

Yes. I have a proxy account with one entry (say, "expenses: bank fees"). They have a proxy account with one entry (say "income: bank fees"). Between the two proxy accounts there are two entries. Money can be neither created nor destroyed.