Is P/E the best metric of a stock’s value?

I'm new to investing and understandably have a lot to learn. I'm read that P/E is a common metric to use in analyzing a stock and that a P/E under 15 (depending on the industry) suggests the stock is undervalued and may rise soon.
Is this accurate? And is P/E a useful metric? Or should I be looking at others?

Thanks in advance!