ABCbits: Thank you for the links, looking at them.

DannyHamilton: Yes, the deep end.  I have a bit of dyslexia and knew that the correct phrase is private key, just wrote it wrong.  I am not a mathematician, or even very good with math.  I just want to develop my own sense of confidence in this entity into which we place so much trust. 

I have a small amount of bitcoins in a commercial exchange and will probably put them in an offline wallet.  Someday soon.

I continue to be a bit surprised at how volatile BTC is, and most cryptos.  Similar to the stock markets of the world, but much more volatile.  Seems to me it should be more stable.  I really do like the concept of a currency that is independent of government control.  That is its main attraction for me.