Many modern symphonies can be encountered only on recordings. Illustration by Richard McGuire

In 1849, Richard Wagner declared, with his usual assurance, that “the last symphony has already been written.” Beethoven’s Ninth, with its eruption of voices in the finale, had, in Wagner’s view, exhausted the form and inaugurated a new age of music drama. The pronouncement went unheeded. In the decades that followed, Brahms wrote four symphonies, Tchaikovsky six, Dvořák nine. After 1900, the idea that nine symphonies represented an outer limit—“He who wants to go beyond it must die,” Schoenberg said, speaking of Mahler’s unfinished Tenth—fell away. Shostakovich produced fifteen symphonies, Havergal Brian thirty-two, Alan Hovhaness sixty-seven. As of this writing, the Finnish composer-conductor Leif Segerstam has generated two hundred and eighty-six (having passed Papa Haydn more than a decade ago, with his Symphony No. 105, “Pa-Pá, Pá-Pa-Passing . . . ”). Composers have also exceeded the seventy or eighty minutes’ duration that was long considered the maximum. Brian’s “Gothic” Symphony lasts almost two hours; Kaikhosru Sorabji’s “Jami” Symphony, which has yet to be performed, would go on for four and a half hours; Dimitrie Cuclin’s Twelfth, also patiently awaiting its première, might devour six.

All this manic productivity notwithstanding, the symphony entered its twilight phase in the years just before the First World War. The modernist revolution launched by Debussy, Schoenberg, Stravinsky, and Bartók took place outside symphonic bounds. With the death of Mahler, in 1911, the symphony seemed to lose the world-shaping power that Beethoven had bestowed on it. To devote oneself to the form was to risk being called a conservative, a nostalgist, a manufacturer of bourgeois museum pieces; twentieth-century symphonies tended to be tonal in orientation and spacious in design, the musical equivalent of landscape painting. When progressive-minded composers took up the symphony, they often did so with ironic detachment. Alfred Schnittke’s First includes mangled citations of Chopin and Tchaikovsky, and Luciano Berio’s Sinfonia makes a surreal collage out of Mahler’s “Resurrection.” More recently, the German-British composer Michael Wolters produced an absurdist piece called “Spring Symphony: The Joy of Life,” which lasts sixteen seconds.

Yet twilight has its satisfactions. In the slow summer months, I’ve been listening obsessively to symphonies on CD, giving particular attention to the twentieth-century aftermath. My stereo has been brooding over the likes of Andrzej Panufnik, Edmund Rubbra, and Eduard Tubin, as well as more familiar fare by Shostakovich, Sibelius, and Nielsen. The question of conservatism is a complicated one. Scholars now routinely ascribe modernist complexities to ostensibly old-fashioned late-Romantic repertory; they are often right, though the category of “modernist” can become meaningless in the process. If Rachmaninoff is modern, who isn’t? The appeal of the form may lie elsewhere, in a skeptical nostalgia that opposes the darker side of modernity.

Of the post-Mahler cycles, the one that has come closest to joining the mainstream repertory is Shostakovich’s. His early symphonies, written under the influence of radical Bolshevik aesthetics, approach the traditional Beethovenian model in quizzical, even sardonic fashion; the Fifth, written at the time of Stalin’s Terror, takes that model in apparent earnest; later works, especially the Ninth, Fourteenth, and Fifteenth, deconstruct it again. The Tenth, which Andris Nelsons recorded earlier this year with the Boston Symphony (Deutsche Grammophon), lies somewhere in between the extremes; its first movement is grim and monumental, but the circus-like finale veers toward a mode that might be called triumphant-grotesque. Nelsons’s recording is the first in a series titled “Shostakovich Under Stalin’s Shadow”; fortunately, he does not labor to wring portentous messages from the score, instead finding a steady pulse of emotion amid the machine rhythms and ironclad climaxes. As often with Nelsons, the phrasing has a vocal shape, and the Bostonians respond avidly.

Nielsen and Sibelius, dissimilar twins of Nordic symphonism (both were born in 1865), have been much recorded of late, on account of sesquicentennial celebrations. Nielsen’s set of six, hyperkinetic and animally alive, are well served by two sharply articulated surveys, one by Sakari Oramo and the Royal Stockholm Philharmonic (BIS), and the other by Alan Gilbert and the New York Philharmonic (Dacapo). Oramo is lithe and precise; Gilbert is more in tune with Nielsen’s furies, especially in his recording of the Fifth Symphony. Sibelius’s seven, the ne plus ultra of symphonic rumination, have benefitted less from the anniversary attention. In the nineties, Osmo Vänskä and the Lahti Symphony recorded a cycle for BIS that, by burrowing into the darkest corners of Sibelius’s world, outclassed all modern rivals. Vänskä is now revisiting the symphonies with the Minnesota Orchestra (again for BIS), but he has yet to match his earlier intensity. A new cycle by John Storgårds and the BBC Philharmonic (Chandos) is altogether too efficient, although Sibelius fanatics will want to explore three recently discovered late-period fragments that are tacked on to the set; cryptic and playful, they hint at the style of the mythic Eighth Symphony, whose manuscript the composer evidently burned in a fit of self-doubt.

Sibelius forever changed the psychology of the symphony, imposing a more introverted, anti-heroic narrative. Few of his countless imitators can match his command of structure, which holds fast even when, as in the Fourth, he is exploring states of extreme psychological unease. If you acquire a taste for twentieth-century symphonies, you become a connoisseur of extraordinary moments that may not add up to a successful whole. Rubbra’s Fourth Symphony, a pastoral British work from 1942, has one of the most magical beginnings in the literature: over gently pulsing dominant sevenths in the winds and horns, strings sustain a simple, triadic motif that bends down like the wings of a wide-spanned bird in flight. Nothing else in the piece is at that level, but I listen to it at least once a year. Tubin’s Fifth Symphony (1946), a metaphor for Estonia’s struggle against Soviet domination, has a stupendous coda: a double formation of timpani, reminiscent of an electrifying passage in Nielsen’s Fourth, propels a seven-note ostinato from near-silence to declamatory thunder, with the brass clamoring above the drums at the end. The preceding music is less remarkable, but I’m content to wait.

Then there are undervalued craftsmen like William Schuman, whose bitterly beautiful Eighth Symphony deserves to be heard as often as anything by his contemporary Copland; or Bohuslav Martinů, whose Third Symphony, from 1944, matches the urgency of Shostakovich’s wartime utterances while avoiding their longueurs; or Panufnik, a greatly gifted Pole who, during the Communist period, took refuge in Britain and struggled to win international renown. The conductor Łukasz Borowicz recently completed an impressive survey of Panufnik’s ten symphonies for the German label CPO, with the Polish Radio Symphony and the Konzerthaus Orchestra Berlin. These works deploy a set of devices that, when you listen in sequence, can seem repetitive: spells of immobile melancholy alternate with propulsive, percussive episodes. Yet each symphony is so impeccably constructed, seldom exceeding the half-hour mark, that you don’t mind the sense of déjà vu. Borowicz’s disk of the Second, Third, and Tenth shows Panufnik whittling his method to a refined extreme. Listeners are likely to return most often to the Third, or “Sinfonia Sacra,” in which Panufnik applies his habitual terseness, his obsessive concentration on small strands of material, to a heart-tugging subject: the old Polish religious hymn “Bogurodzica,” or “Mother of God.” When the full melody rises majestically out of the orchestra at the end, the effect is not merely sentimental; it feels like the proof of a theorem.