It’s a good idea to prepare yourself if you plan to see both parts of Mr. Lopez’s play at matinee and evening in the same day. It can be done at 1 p.m. and again at 7 p.m. Make certain you’ve had sufficient nourishment to get you through, and you might consider a visit to the rest room before you settle in —to give your bladder a break as well.

As Part One begins on a reasonably bare stage, we meet a group of gay men sitting around writing; one of them is having trouble getting started. E.M. Forster enters as a professor of literature (seen only in the imagination of that young man) who admits he does not know how to start the novel he has been planning for some time.

The youth is a Forster fan, and he is familiar with his masterpiece “Howard’s End.” On advice from the ghostly writer, he decides to start in a similar manner by changing the word “letters” that opens the 1910 novel to “emails” from his friend; and we are off on the long search for truth in the life of the young writer. Living in the present day, he owes much to the values and attitudes he and his friends have inherited from the gay segment of the later 20th century. Without their sacrifices and suffering he could not enjoy his life style openly.

For the next six hours he will live out and share with us the novel he finally completes which covers over two years of his 21st century life presented as fiction but based on his own experiences.

Stephen Daldry is a superb director of plays. “Skylight ” and “Billy Elliot” are examples of his ability to handle small, large and varied material onstage as well as sharp characterizations on film (“The Hours,” TV’s “The Crown”).

Here he has managed an enormous company of over 30 actors to stage this epic drama which is engrossing and interesting. Its enormous size is made even more noticeable by the simplicity of the physical production; the dozens of locations called for in the script are clearly conveyed to us by the simple movement of a chair, a shift in the lighting, the use of a doll house to represent a mansion, and a model cherry tree.

The exposition comes in scene after scene which the actors convey to us at times by addressing us directly with story points. These help create the various links that take us into the life stories of several characters that Lopez has put under the lens.

We learn of a section of the young gay men in the 1970s and ’80s who burst from their closets and went somewhat wild. They thought they were celebrating their late century freedoms, taking full advantage of the affordable and available chemical mixtures that lowered inhibitions and raised energy levels until the dark day when the HIV virus entered the dialogue and the bloodstreams of so many of them.

It’s the writer’s contention that later gays are the inheritors of ever-increasing acceptance to the point where they can tell stories like these, write plays exposing all aspects of their existences, become visibly involved in politics, corporate and family life. He’s done a fine job of capturing the words and actions of this fraction of the gay population.

A splendid cast of mostly unknown actors brings vivid life to a broad range of characters. He begins with English novelist E.M. Forster — a ghost from the early 20th century — here known by his middle name of Morgan. As Lopez writes him, he acts as a guide to the young people of the author’s generation as one of this group, a novelist, is searching for a way to tell his story.

The play, in two parts, each more than three hours long, is inspired by Forster’s 1910 novel “Howard’s End” which deals with connection to the past. It’s Lopez’s conviction that his generation of gay men needs to connect to the generation before them, the one that lived and died during the plague that caused immune deficiency — the plague called AIDS.

The first characters he introduces to us are Eric Glass and his wildly extroverted boyfriend Toby Darling, a gifted young playwright. These two are played by the talented Kyle Soller and Andrew Burnap. They are shining examples of the excellent actors, many of whom have come to us from the original London production.

The acting throughout is of the highest order, even though I found the writing of the vast number of characters to be often sketchy and incomplete. An odd tool for Mr. Lopez is the monologue. In each half of the two-part play, he has written one which adroitly combines exposition with vivid imagery but lasting lengths usually not heard on stage.

The monologue in the second half is given by the gifted Lois Smith who describes her life with her son who had succumbed to AIDS some years ago. Her story is presented with all the vivid detail that only a devoted mother could express, and Ms. Smith has us waiting on her every word because she makes every instant of it shatteringly real.

In like manner in the first half, Paul Hilton brings to his character the same ability to hold us on a tight rein with an uninterrupted flood of words. Both monologues break the rule as I know it — that it’s better to show us than to tell us. But then everything about this seven hour work makes no apologies for playing by its own rules.

I found myself meeting it half way. I was informed and moved by much of it and vastly confused by the rest. It speaks about a circumscribed section of the gay community with which I found it difficult to connect. I lived through all the periods the play covers. But the hedonistic excess that the play presents seemed as foreign to me as though I’d not been there at all.

There is so much to admire in the direction, the design, the performance, and in much of the blistering dialogue. The play’s enormous success in England indicates it well may enjoy the same here in New York.

I respect it, and it makes a valuable contribution as a fight against complacency. For the most part it held my interest despite its great length. But I also felt distanced from much of it.

The Ethel Barrymore Theatre, W. 47th Street.

Each of two parts runs approximately 3 1/4 hrs. With two intermissions. Open run

Connecticut Media Group