Caution: Power Supplies!!

[Milliams]

Most books I've seen for modules n'stuff, recommend that I start building a
+/-15v power supply. But somewhere in the design it says "Caution: If you are
unskilled at working with 110v AC, do not attempt this project!!". Well, if
it is logical to start with the power supply, how do I become "skilled at
working with 110v AC"?

Sincerely,
A cautious (don't wanna die!!) boy