Regular readers of the Chronicle may not expect to learn a lot that they didn't know already, but they will likely be surprised, especially when it comes to the deleterious effects of alcohol. Did you know about the nasty effects of acetaldehyde? I didn't. It's what you get when you metabolize ethanol (alcohol), and it's carcinogenic and damages internal organs. Because it is so damaging, the body breaks it down into acetate, but if you're drinking at the rate of more than a drink an hour, you're body starts lagging behind. Something to keep in mind the next time someone invites you to join a drinking contest.

Similarly, you may share the general conviction that alcohol use can lead to violence, disease, crime, and accidents, but "Marijuana Is Safer" offers up the hard numbers -- complete with footnotes. Here's just one hard number: 35,000. That's the number of deaths each year attributed to chronic alcohol consumption. We all know what the number of deaths attributed to chronic use of the chronic is, don't we? That's right, zero.

Armentano, Fox and Tvert offer a mix of history, science, medicine, media critique, and just plain straight talk as they survey the history of alcohol and marijuana use in America, discuss the differing attitudes toward the two drugs, explain the rise of marijuana prohibition, and, most centrally, compare and contrast the effects of the two drugs on individual consumers and society as a whole.

They also dissect the arguments that legalizers have used -- so far, unsuccessfully -- to try to end marijuana prohibition. While those arguments are perfectly valid, the coauthors argue that they cannot counter the objection of people who might otherwise be persuaded: Why should we legalize another vice?

Naturally enough, Armentano, Fox and Tvert have the answer: "We would not be adding a vice; we would be allowing adults the option to choose a less harmful alternative for relaxation and recreation," they write.

They also provide the "money quotes" for several other skeptical responses to a legalization pitch, all designed to highlight the comparison of alcohol and marijuana. And these three are extremely well-positioned to know what to say; all three have been engaging in this conversation for years.

The coauthors also make a compelling argument that the "marijuana is safer" approach is a winner precisely because it forces listeners to think about alcohol and what it does -- something that all Americans know quite a bit about even if they don't drink. The comparison of marijuana and alcohol brings the discussion down from lofty abstractions about freedom and liberty to real world experiences with America's most popular drugs.

The "marijuana is safer" approach works just fine for marijuana, but potentially subverts broader anti-prohibitionist politics. It is difficult to imagine an argument for drug legalization based on "methamphetamine is safer" or "heroin is safer." It also effectively throws up a wall between "soft" marijuana and "hard" other drugs, abandoning broader drug legalization for freeing the weed alone. But perhaps "abandoning" is the wrong word. After all, Armentano and Fox work for marijuana reform organizations -- not drug reform organizations -- and Tvert's work all along has been about marijuana.

But possible unhelpful side-effects for broader anti-prohibitionism aside, "Marijuana Is Safer" is extremely worthwhile. This is a book you can hand to your mother or your teacher or your preacher and provide him or her with a nice framework for looking at marijuana -- one that by its inexorable comparative logic leads to the inescapable conclusion that marijuana should be legalized.

And for those readers with an interest in activism, this book needs to be on your bookshelf. It's full of handy, well-documented facts, it's got the answers to the questions you're likely to hear, and it's even got a how-to activism section at the back. I guarantee that if you own this book, it's going to be very well-thumbed before very long.