All marijuana is not the same, a new book says. (Bigstock)

Cannabis Pharmacy: The Practical Guide to Medical Marijuana” doesn’t read like your standard medical self-help book. Take, for example, Part 3, “Varieties of Medical Cannabis.” It begins in a traditional manner, by explaining why different varieties of weed might help different conditions.

But it goes on to tick off their merits over 60 pages of names that sound like the track list for a ’70s album: Grand Daddy Purple is “excellent for bed rest and recovery,” Bubba Kush is “an outstanding choice for pain and nausea,” and Haze is good for daytime use “since it results in little cognitive impairment.” Each of 27 varieties is rated for ease of cultivation, aroma, taste, potency, duration, psychoactivity and other qualities. There’s also a brief history, letting you know, for instance, that Malawi Gold is that African nation’s third-biggest export, and Purple Urkle seems to be named for Steve Urkel, the most popular character on the old sitcom “Family Matters.”

Part 4 runs through how cannabis might be used to treat several dozen medical conditions — including asthma, cancer, HIV/AIDS and schizophrenia — noting that the most common use to this point is, simply, to relieve pain.

A lot of ground is covered in the rest of the book: the chemical makeup of marijuana’s active ingredients, how marijuana is metabolized, how it should be stored, common and uncommon adverse effects, conventional vs. organic options, advice on using it on the job. There are numerous drawings, graphics and charts.

It’s all hard to evaluate. For one thing, in this new era of widespread medical marijuana use, “experts” tend to come from places other than the Mayo Clinic or the National Institutes of Health; like computer hackers, a lot of these people have developed their skills outside the mainstream. Michael Backes, who wrote this book, is described on its cover as the founder of “the first evidence-based medical cannabis dispensary” and a specialist in cannabis science and policy issues at a Southern California consulting firm. For what it’s worth, his impressively long appendix includes citations from the Lancet, the Journal of Psychoactive Drugs, the Proceedings of the National Academy of Sciences and scores of other journals and books.