Happiness, or subjective well-being (SWB), as academics prefer to call it, is a universally cherished goal. Some philosophical books, such as classic Buddhism, condemn the pursuit of happiness and consider it a reproachable waste of time in which an enlightened person should not engage. However, such elitist doctrines cannot have been easily embraced by the masses. Throughout the world and regardless of their religion, most people would like to attain a state of bliss here and now and, in contrast to classic Buddhist pundits, are not deterred by the certainty of its transience.
Ok, first off, I'm not sure what "classic Buddhism" is. That's like saying "classic Christianity". Does the author mean Mahayana? Or Theravada? Nichiren? Zen? Pure Land? What would "classic Christianity" refer to? Catholicism? Which kind? Greek Orthodox? Roman? Or would it mean Protestants? You get the idea.
Secondly, as I understand it, I don't think buddhism condemns "the pursuit of happiness as a reproachable waste of time." It's kind of unfortunate to read this in this book, because many of their observations had been spot-on until that point. It's tough to read stuff like that in a book because it makes me wonder where else their bias has been showing through.
So, in my understanding, what does buddhism say about happiness? One of my favorite podcasts that I recall listening to talked about stages toward enlightenment and while I don't recall the specifics, it went something along the lines of giving up _____, which also meant giving up its opposite. Perhaps "giving up" is the wrong term, but more of releasing. So, to rid yourself of sadness, you need to release your attachment to sadness, release sadness itself. But! If you're going to release your attachment to sadness, you'll also find yourself releasing your attachment to happiness. Why? Because you start to see that attaching to one as futile as attaching to the other - it's trying to hold on to something that's transient. The end state is equanimity - you are happy - you are sad - they're not the same, but wanting to always have one and never have the other is delusion. I might be sad tomorrow. I might be happy the day after that. They come, they will go. It's not to say I don't want to be happy, but there are causes and conditions that give rise to happiness and sometimes I'm powerless over them. Most of the time, I'd wager.
Reproachable? Hardly. Waste of time? Not really.
Just because I know "happiness" is transient doesn't mean I don't want to be happy and don't try to be happy. I just know that it won't last and so, when it goes, I accept that.