Few modern composers have created more enchanting melodies than Sergey Prokofiev, who wrote the sprightly “Peter and the Wolf” for narrator and orchestra, the swaggeringly romantic ballet “Romeo and Juliet,” and the zesty, ultra-Russian “Lieutenant Kijé” suite. Yet in his “Memories and Commentaries” co-written with Robert Craft, Igor Stravinsky refers to Prokofiev’s “lack of intellect and culture” and quotes the ballet impresario Serge Diaghilev as believing that Prokofiev was “stupid.” Part of this attitude may be based retrospectively on the fact that Prokofiev, who left Russia in 1918, decided to return for good in 1933, only to find himself a victim of Stalinist thought control. He was pressured to compose propaganda works like the cantatas “Zdravitsa” (“A Toast”), written in 1939 to celebrate Stalin’s 60th birthday, and in 1947 “Flourish, Mighty Land,” to mark the 30th anniversary of the October Revolution. Which is the real Prokofiev, the youthful melodist of genius or more mature Stalinist puppet?

Prokofiev has just been given a chance to explain his aims and origins in his newly published “Diaries 1907–1914: Prodigious Youth” (Cornell, 835 pages, $45), translated by Anthony Phillips, the first of three planned volumes totaling about 750,000 words. These diaries, seized by the Soviet government after the composer’s death in 1953, were hidden in Soviet State Archives until Prokofiev’s son Sviatoslav was given permission to transcribe them. The diaries cover Prokofiev’s student years at the St. Petersburg Conservatory, including dealings with teachers and composers like Alexander Glazunov (1865–1936) and Nikolai Tcherepnin (1873–1945). Doughty verbiage and plain speaking — rather than any notable literary skill — give these self-conscious accounts, including many sub-Chekhovian character portraits, their inherent interest.

Young Prokofiev wasted no idol worship on his professors, calling Glazunov a “hopeless drunk,” while referring to a piano teacher named Winkler as “more like a Stinkler than a Winkler.” Yet his talent was inarguable, as he produced the delightful early First and Second Piano Concertos, First Violin Concerto, and “Classical” Symphony. Passionate about momentum and quickness in his quest to become a self-made hero of Russian music, Prokofiev uses the word “cinematographic” in 1911 as praise for the rapid action in a play he wants to set to music. On a 1913 trip to Paris, he writes, “The countryside flashed by with cinematographic speed, while the train seemed to be going faster and faster until I was brought to a state of ecstasy.”

This joyous dynamism is also evident in the diaries’ many discussions of chess, which Prokofiev studied until he was able to defeat the world’s dominant chess player, José Raúl Capablanca, in 1914. So much for Stravinsky’s allegations. Yet Prokofiev’s taste in music was less assured. He did not consider Strauss’s “Don Quixote” to be “music at all.” Debussy’s music is “all very similar, and in that sense it is boring,” says Sergey, adding that Ravel’s ballet “Daphnis et Chloé” has “so much water in it, its contours are so diffuse, that all in all it is not worth listening to.” Among the few composers he approved of were Tchaikovsky and — in brief excerpts — Wagner, and he patiently read through books about Tchaikovsky and Rimsky-Korsakov in order to inspire his own composing.

Another classic motivation of young composers — Eros — is scarce in this account of his youth. Sergey enjoyed romantically teasing young women, sometimes to the point of cruelty, describing one fellow student as living “in continual dread of my making her the butt of my teasing and jokes.” Yet he primly avoided actual physical encounters with women. Many pages are devoted to his passionate friendship with a young pianist, Max Schmidthof, who eventually committed suicide. A recent well-documented biography by David Nice, “Prokofiev — A Biography: From Russia to the West 1891–1935,” quotes Prokofiev’s widow as explaining that Schmidthof was gay and Prokofiev himself had “such tendencies,” though she doubts he had any “affair with a man.” The persecution of sexual minorities is still alive in Russia today. In Prokofiev’s time, unorthodox desires, even suppressed ones, might have served as further incentive to toe the Stalinist line, though Prokofiev — unlike Shostakovich — never officially joined the Communist Party.

After reading this profusely conflicted, sardonic diary, it is refreshing to listen to Prokofiev’s music, such as the composer elegantly playing his own Third Piano Concerto (Naxos) and Dimitri Mitropoulos passionately conducting the ballet “Romeo and Juliet” (Sony Classical). Pierre Monteux leads the “Classical” Symphony with effervescent glee (Music & Arts), and the commanding Russian violinist Nathan Milstein plays the concertos (EMI Classics). Glenn Gould performs the Seventh Piano Sonata with uncommon lightness (Sony Classical), and Sviatoslav Richter offers a magisterial Sixth Piano Sonata (RCA Red Seal). Even after the remaining two volumes of his diaries finally appear in English, Prokofiev the man may still remain a mystery, but his finest music will dazzle listeners — and our best musicians — for generations to come.

Mr. Ivry is author of biographies of Francis Poulenc and Maurice Ravel. He last wrote for these pages on Shakespeare’s “Merchant of Venice.”