Many of today's high-net-worth investors are turning their attention to early-stage investing in emerging companies. They know just how successful and lucrative funding a start-up venture can be. Savvy angel investors can foresee distant but potentially huge returns from pre-IPO companies. There are scores of hungry entrepreneurs in search of capital and lots of money to be invested. But, matching the right entrepreneurs with wise investors, so that both can profit, is the challenge in new enterprises.

Gerald Benjamin and Joel Margulis demonstrate that the real pitfall for potential...