It's true that "Join the rentier class" is not a complete investment strategy all by itself--but dig into Wise Bread's archives, and you can get most of the pieces of one.

I'm sharply attuned to the risks of inflation. (The modern inflationary peak in 1980-1981 came just at the point when I was setting up housekeeping for the first time in my life. I remember vividly what an inflation rate over 12% does to a household budget.) But the fact that there is inflation doesn't make investing for income invalid, it just means that you can't take the returns at face value--you have to do a little mental arithmetic first.

There are a lot of other income investments besides the two categories I mention (treasuries and dividend-paying stocks), but they're the only ones I feel comfortable recommending without a lot more information about how to research them. The others have their place, but any that pay a higher return are naturally going to carry higher risk.

As long as you have your emergency fund (for emergencies) and your maxed-out 401(k) (for retirement), you're in a position to take some risks. If you're comfortable with that risk, go for it. But, if you're not, then my whole point is that people can join the rentier class in a small way without needing to take the high risks that might (if the reward matches the risk) let them join the rentier class in a big way sooner.