Often dazzling in its beauty and at times frustratingly difficult, “Middle C” is like no other book that will be released this year or, more likely, this decade. Almost 20 years in the making, William H. Gass’ new novel is a richly rewarding read and a remarkable meditation on misanthropy and identity.

“Middle C” opens in 1938 Austria, where Joseph Skizzen’s father decides to make Jews of his family so that they can escape the nation and reject complicity in Nazism and the war. “To desire an Austrian nationality is to accept the acts of assassins, tacitly to agree to — my God — mayhem and massacre,” he tells his wife.

“When we left Graz,” his father “would maintain, we undid our ties; we left our prior selves behind like old clothes on their way to rags; we joined the dispossessed, yet were not one of them either.”

His father moves seamlessly between characters, taking up one identity and casting away another. But in the process, he casts off his family and leaves them as immigrants in London while he disappears.

Joseph and his mother and sister make their way to America, and the family settles in Ohio. Joseph learns to play the piano, becomes a professor of music and develops an elaborate fantasy display in his attic — an Inhumanity Museum of old newspaper clippings to “remind its visitors of the vileness of mankind — not its nobility and its triumphs but its vulgar greed, stupidity, and baseness.”

And over the course of his life, Joseph furiously rewrites a single sentence, a “perpetual variation of a single idea” that encapsulates his despair at humanity: “The fear that the human race might not survive has been replaced by the fear that it will endure.”

The novel modulates between Joseph’s present life as a professor and his past. But at the center of these two narratives is a radical interrogation of identity and Joseph’s apparent lack of one. Skizzen, after all, is the German word for sketches.

“During Joseph’s many pensive moments in the library, he … began to realize that his friends would see him as they saw a Christmas package, decorated to entice but wrapped to conceal. By giving himself youthful myths and minor mystifications, he had donned, in effect, a powdered wig and a false nose.”

The range of the novel and its operatic beauty is a wonder and enriched by Gass’ ability to render a range of tones that harmonize seamlessly together.

The novel is many things at once: an immigrant’s narrative and a bildungsroman, a campus comedy and a tragedy, an exploration of the boundaries of human identity and a meditation on man’s fallen nature.

Beyond the text’s thematic richness, readers will certainly be rewarded by the strength of the writing and the breadth of his vision. Gass’ linguistic virtuosity is really a wonder to behold, and the novel is replete with gorgeous descriptions of gardening and music:

“For several weeks (Joseph’s) mind moved — larghissimo — like the slowest sections of symphonies. How often would an answer be repeated by the cello and like a rising woodwind exit as a query?”

But this is by no means a perfect book. Gass, now 88, an eminent critic and long a fixture at Washington University in St. Louis, is the type of writer who must be approached with a fair amount of deference.

But he’s a writer’s writer, which is to say that he’s always been more popular with other authors than with the public, in large part because of how difficult his works can be. In fact, in a 2005 interview with “The Believer,” Gass said, “The reader is somebody I don’t pay much attention to.”

And, in true Gass form, “Middle C” can often frustrate the reader, especially in its defiance of narrative conventions. Where Gass’ loyal readers will find richness and symbolic meaning, general readers might encounter pedantry and obscurantism.

As the saying goes, it’s no use arguing over tastes, but “Middle C” is anything but eminently readable.

Of course, readers of all tastes should be able to delight in Gass’ extraordinary use of the English language, the rich cadence and poetry of his words. And “Middle C” is well worth reading for this alone.