ICOT, I just checked, and I have a copy of a Time/Life book called Basic Wiring from 1978, I believe. I passed by a garage sale a while back, and it was like a dollar or so, so I bought it. Very helpful, and probably very similar to the book you mention.
The theory of electric wiring is very straightforward, however, I don’t have shimush (practical experience). What was bothering me was the use of those caps, which seem like such a poor and unreliable way to connect wires compared to soldering. In electronics, you would never ever wrap wires to make contact. Either you would solder to a terminal, or screw it on to something. If you needed to connect multiple wires like for lights, you would connect short leads to each screw terminal, from light to light in parallel. There is nothing stopping you from screwing multiple wires to a single terminal.
So for house wiring, I have done the things that involve screws, like outlets and switches, but that assumes the right wires are right there. However, when you have to plan for multiple connections on one line or box, you can’t screw multiple 14 gauge wire onto one screw. I doubt it would fit or hold properly. So from reading the book, I see that the use of these caps is industry standard for everything, and not considered shoddy.
My questions are when you have to connect multiple wires (3 or more in one splice) what is the best way. You mentioned a wire nut. Please explain what that is in more detail. Also, when working with caps, do you twist the wires first, or simply place them side by side and twist the cap over them. Do they make caps meant for multiple wires together?