A consumer’s guide to the best and worst of sports media and merchandise. Ground rules: If it can be read, played, heard, observed, worn, viewed, dialed or downloaded, it’s in play here.

What: “The Ball”

Author: Daniel Paisner (Viking, $29.95)

“Going, going, gone . . . for $3 million”

That’s a headline describing the auction of Mark McGwire’s 70th home run ball of 1998.

Paisner skillfully describes the flight of the ball after it was run down by a spectator, Philip Ozersky.

On the collectibles market, it was now a screaming No. 1. An heirloom. A Honus Wagner trading card times two, as Paisner put it.

The offers for a private purchase began at $1 million and skyrocketed. It went to auction, 107 days after Ozersky had picked the ball off the floor in the suite where he’d watched the game. Sale price: $3.005 million. The buyer was sports collector and comic book artist/writer Todd McFarlane.

Lots of fascinating characters here, such as guys in the left-field bleachers carrying up to $20,000 cash in valises, hoping to make on-the-spot cash buys of McGwire or Sammy Sosa late-season home runs.

Of special interest are accounts of the manufacturing of the 90,000 dozen baseballs used by major league clubs each season. They’re made in a Costa Rican factory.

Then there were the high-tech efforts to authenticate each baseball used in Cardinal games, as McGwire closed in on 70. It was done with sequential, invisible stamps, readable only with infrared light.

This is an enjoyable read, but you’re left with the thought: Is there no end to the assigning of monetary value to the scraps of sports’ flotsam and jetsam?

Apparently not. McFarlane, right after buying McGwire’s 70th, began negotiations to buy Sammy Sosa’s and McGwire’s 64th home run balls.

Then there’s this: The Cardinals’ lineup card for the game in which McGwire hit his 70th was auctioned off for $29,900.