By invitation, back in June, Solares Hill sat in on the auditions for “August: Osage County.”

We also attended in the fall the first read-through by the cast of Tracy Letts remarkable play. And at the end of last week, just before press time, we watched the unveiling of its opening act at Waterfront Playhouse.

What a sensational evening. This is a hilarious piece of serious theater. Serious in the sense of, for example, Eugene O’Neill. Hilarious in the sense of, say, Lenny Bruce.

Where it careers beyond O’Neill and even Bruce is in its grasp of what has become of America over three generations of our own time: the anxiety generation of World War II and its aftermath, the narcissistic generation of the 1960s and the millennials of now. The play won a Pulitzer Prize and a Tony Award for its author. The director, Danny Weathers of the Waterfront, took an ambitious risk bringing it to Key West. But every one of the performers not only rises to the occasion, they leap to it.

Joy Hawkins is particularly fabulous as the pill-popping matriarch of the Weston family — watch her dance to Eric Clapton! Very good too is John Wells, her husband in real life and in the play, as the soon-to-be-dispensed patriarch.

George diBraud is completely right as their elder daughter and so is Jessica Miano Kruel as her daughter and Bob Bowersox as her husband. On the Aiken side of the family, Chris Stone is terrific as the aunt and Tom Murtha utterly realistic as her long-suffering hubby.

Shakti Assouline is a stand-out as the Cheyenne help, perhaps the only sober role in the play along with the Weston’s middle daughter, excellently played by Stephanie Yosen, and the town sheriff, the likewise excellent Joe McMurray.

Nicole Nurenberg and George Murphy as a May- September couple and Kyle Caskey as the forever-young Aiken own their roles to the extent that it’s now impossible to imagine anyone else in them. Satisfaction guaranteed.

The set by Michael Boyer is another character in this production. Designed to incorporate three stories with the ground level showing three living spaces, it’s an engineering marvel that nevertheless suggests the reality behind the scenery, which is that the house’s foundation is falling apart and the shades make a night out of every day.

Yet another character in “August: Osage County” is the author’s language. What O’Neill did for the northeast, Tracy Letts is doing for the hinterland. Some of the lines are simply too true to be good: Pills “illuminate her need for equilibrium.” Some are sweet: “Books are like finding wild onions on the side of the road, or unrequited love” (or was that “requited?”). Some are bitterly ironic: “Genocide always seems a good idea at the time.”

Assuring us of the play’s literary chops, the program contains a quote from Robert Penn Warren’s “All the King’s Men” that provides the philosophic backstory: “It is a kind of blood greed … It is the thing which man has that distinguishes him from the happy brute creation. When you get born your father and mother lost something out of themselves, and they are going to bust a hame [harness] trying to get it back and you are it. They know they can’t get it back but they’re going to get as big a chunk out of you as they can.”

To each of the cast of “August: Osage County” go our profoundest congratulations. And to the director and the set designer, and to costume and props designer Carmen Rodriguez, lighting designer David Bird and to stage manager Trish Manley go kudos of the highest order.