Morningstar Guide To Mutual Funds (Wiley-2003) (pdf)
wouldn’t buy a new home just because it looked good from the
outside. We would do a thorough walk-through first. We’d examine the fur-
nace, check for a leaky roof, and look for cracks in the foundation.
Mutual fund investing requires the same careful investigation. You need
to give a fund more than a surface-level once-over before investing in it.
Knowing that the fund has been a good performer in the past isn’t enough
to warrant risking your money. You need to understand what’s inside its
portfolio—or how it invests. You must find out what a fund owns to know
if it’s right for you....