I craved good advice one summer when I fished a little-known midwestern river full of brown trout. Every few days I went to the local fly-fishing store and asked the guys who worked there where in the river the really big fish I had heard about might be. The guys were friendly, and more than willing to sell me stuff, but when I asked that question I met the mason-jar expression I've described. I tried being winsome; I portrayed myself as fishless and pitiable, told jokes, drank coffee, hung around. On the subject of vital interest, nobody offered word one.

I halfway gave up and began driving the back roads aimlessly. Then just at sunset one evening I suddenly came upon a dozen or more cars and pickups parked in the high grass along a road I'd never been on before. I pulled over, got out, and crashed through the brush to investigate. There in a marshy lowland was a section of river I had never tried, with insects popping on its surface and monster brown trout slurping them down and fly rods swishing like scythes in the summer air. Among the intent anglers along the bank I recognized the fishing-store owner's son, one of the mason-jar-smiling regulars. The experience taught me an important outdoor fact: Regardless of what the people who know tell you or don't tell you, an off-road gathering of parked cars doesn't lie.

In case you're wondering, this particular good fishing spot was on the Pigeon River near the town of Vanderbilt, Michigan, upstream from the dam. It's been years since I fished there, so I can't vouch for the up-to-dateness of my information. But unlike smarter outdoorsmen, I am happy to pass along whatever I can because I myself am now gabby and free with advice to an embarrassing degree. I noticed the change as I got older; I hit my midforties, and from nowhere endless, windy sentences of questionable advice began coming out of me. An old-guy voice takes on its own momentum, and I seem unable to stop it even when I have no idea what I'm talking about. Sometimes when strangers ask me for directions on a hiking trail or just around town, I give detailed wrong answers off the top of my head rather than admit I don't know. When my hearers are out of sight my reason returns and I realize what I've done. Then I make myself scarce, for fear that they will discover my ridiculousness and come back in a rage looking for me.

Outdoor magazines I read as a child featured authoritative fellows in plaid shirts and fedoras who offered sensible tips about how to find water in the desert by cutting open cacti, how to make bread from cattail roots, or how to predict the weather by the thickness of the walls of muskrat dens. I wish I had down-to-earth wisdom like that to impart, but when I search my knowledge all that comes to mind is advice that would cause me to run and hide after I gave it. The one piece of real advice that I do have is not outdoor advice, strictly speaking; I think, however, that its soundness makes up for that drawback. It is true virtually every time, in all lands and cultures. I offer it as the one completely trustworthy piece of advice I know, and it is this: Never marry a man whose nickname is "The Killer."

Other than that, you're on your own.

Ian Frazier's latest book, On the Rez, will be published in January by Farrar, Straus & Giroux.