Tony Abou-Ganim has been mixing cocktails for 30 years, but he still relies on the same rule of thumb for what defines a good drink: "If the person you serve it to tries it, smiles and their eyes light up, you're onto something."

Introduced to the upper-class restaurant scene via celebrity chef Mario Batali, Abou-Ganim is now one of the giants in his industry, yet his new book, "The Modern Mixologist" (Agate Surrey, $35), makes cocktails accessible. There is no insider's regalia; there are no navel-gazing anecdotes. Aptly named, "The Modern Mixologist" is a guide to being just that.

We recently dialed up the jet-setting author at his home in Las Vegas to chat.

Q: In your mind, what's the difference between a bartender and a mixologist?

A: I think ultimately, what we do is tend the bar. I was a bartender for years before I even knew of the word mixologist. There are all different types of bars and all different types of bartenders, which is one of the beautiful things about our industry. But when one becomes very passionate about the art and science of the profession, I believe that the term mixologist applies.

Q: In your introduction, you remind readers that all cocktails are built from a base spirit, and accoutrements are an afterthought. What's the good example?

A: I would say the drink on the [book's] cover, the cable car, which is probably my best-known original cocktail. It follows the basic recipe that was first given to us in the mid-1800s for a drink called the brandy crusta, which is basically a base spirit, orange liqueur and citrus.

Changing the brandy to gin gave us the white lady, changing it to cognac gave us the sidecar, changing it to tequila has given us the margarita, changing it to citrus vodka has given us the cosmopolitan, and changing it to spiced rum has given us the cable car.

Q: Your brass rail cocktail is named for the bar at which you first worked, more than 30 years ago.

A: I'm so proud of how far the profession has come in those 30 years. When I started, you told people you were a bartender, and they said, "What do you want to be when you grow up?" Now, young bartenders are professional and passionate and exciting.

Q: What makes a cocktail worth making again and again?

A: My dear friend Steven Olson once told me, 'Keep an imaginary bookshelf in your mind.' Remember flavors, like cooking. Balance is a big secret to making great cocktails. And a lot of love.