What an extraordinary act of scholarship and imagination Boston Baroque’s Martin Pearlman has achieved. In creating his own "performing version" of the second of Monteverdi’s three surviving operas, the 362-year-old Il ritorno d’Ulisse in patria ("The Homecoming of Ulysses"), and presenting what were probably its very first Boston performances, he not only had to conduct it but also to orchestrate the entire score, since the sole surviving copy indicates only the vocal and bass lines. He created a rangy continuo section (archlutes, gamba, cello, organ, and two harpsichords) to accompany the extensive recitatives (Monteverdi’s audience was probably expecting something more like a sung play than continuous operatic singing) and a small orchestra (in which two recorders and a bassoon-like dulcian were the only non-stringed instruments) for the arias, duets, and ensembles and the non-vocal passages. He did a superb job, using only bass, gamba, cello, and organ, for example, to suggest the watery depths from which Neptune arises, or strings only, trembling or sustained, in the great scene where Ulysses strings his bow and kills Penelope’s suitors.

The plot, derived from the Odyssey (complete with interference from the gods), is Monteverdi’s most touching and expansive work, practically Shakespearean in scope (or Verdian — this is the beginning of real Italian opera) and complexity of tone: more humanly emotional than Orfeo, not as cynical or satirical as L’incoronazione di Poppea. And though nothing is more ravishing than the best music in Poppea, Ulisse is still Monteverdi at his most seductive. And varied. Comic scenes and a heady, youthful love scene interrupt the general tone of poignant longing ("In the end, every love is fatal," Penelope sings). Pearlman can be a maddeningly timid and mechanical conductor, but this time, his rhythmical vigor and dramatic contrasts of timbre and tempo (even within a single aria) made for a riveting three hours.

I can’t remember seeing an opera in which a large cast was so consistently satisfying. There was no one who wasn’t excellent — even some singers not yet out of school, like Brazilian countertenor José Lemos (as a pathetic Human Frailty) and mezzo-soprano Kristen Faerber (as Melanto, Penelope’s love-sick maid), both master’s candidates at NEC, and the vocally well-endowed and versatile tenor Tracy Wise from BU’s Opera Institute (as the Falstaffian pillow-bellied glutton, Irus).

Some of Boston’s most familiar singers were outstanding: brilliant soprano Sharon Baker as the flirtatious and fickle goddess of Fortune and a commanding Juno; endearing mezzo Pamela Dellal as Penelope’s Nurse Eryclea, who’s just dying to reveal her secret knowledge of Ulysses’s identity; tenor William Hite, usually a romantic lead, as both one of the slimeball suitors and a powerful, restrained Jove; tenor Frank Kelley, more frequently a slimeball, but in happily refreshed voice as another suitor; resonant Boston Camerata bass Nicholas Isherwood, as much at home in early music as in Stockhausen or Messiaen, deliciously repellent as the third suitor; and young Jeffrey Thompson as Eurymachus, Melanto’s hormonally rampant lover (their sexy love duet added real heat to the proceedings).

Tenor Lynton Atkinson didn’t impress me as Don Ottavio in Boston Baroque’s 1997 Don Giovanni (he also sang the title role in Pearlman’s Orfeo last year), and he still has some trouble maintaining enough breath to support his top notes. But with his appealing lyric voice and intelligent acting, he was sympathetic as a worn but still virile Ulysses. Yet another tenor, Mark Tucker, making a startling entrance from the back of Jordan Hall, excelled as an eager, impassioned Telemachus. Mezzo Christine Abraham, so impressive as the betrayed lowly heroine in last year’s Boston Lyric Opera production of Tod Machover’s Resurrection, made an astonishing transformation to the regal, all-knowing Minerva. Gustav Andreasson, a real bass with a ringing, depth-charge low C, made a big hit as both Time and Neptune (he’ll be back in town next week as the lecherous harem guard Osmin in BLO’s Die Entführung aus dem Serail). Light-voiced soprano Amanda Forsythe made a charming Amore. And animated, more-baritone-than-tenor William Watson, from the Chicago Lyric Opera, almost stole the show as Eumæus, Ulysses’s devoted, compassionate swineherd.

But the biggest hand went to mezzo Phyllis Pancella in Monteverdi’s greatest role, Penelope. In her Italian-black mourning dress, she looked like a young Anna Magnani, and she’s a volatile actress effective in a number of styles, from realistically detailed, to comic eye rolling, to high tragic (her other roles range from Carmen to Sweeney Todd’s murderous Mrs. Lovett) — you can’t take your eyes off her. And her sizable voice, despite a few rough patches, could be both agile and melting. When Penelope finally comes to recognize her long-absent husband, Pancella was heartbreaking.

All these singers were extremely musical, responding effortlessly to the orchestra (just as the splendid on-stage players, whenever I glanced over at them, always seemed to be responding to the action). They were also word-oriented and emotionally focused — an ideal combination not often achieved. And they were in good hands with stage director Mark Astafan, whose minimalist directorial touches, in the pared-down, smartly anachronistic style perfected by William Christie’s Les Arts Florissants (contemporary dress, from evening gowns and tuxes to black jeans, reflecting social status; no props or furniture except for a chair in one scene), allowed the singers to be both stylized yet emotionally uninhibited. I didn’t think some of the miming worked — Ulysses’s invisible bow seemed to be a different size and weight for everyone who "held" it or tried to string it. But the most important things, as on every level of this memorable event, were right on target.

AT SYMPHONY HALL, 17-year-old Boston violin prodigy Stefan Jackiw made his official BSO debut (he played at the Pops when he was 12) in the Mendelssohn E-minor Concerto at a single Tuesday subscription concert, filling the spot where Mitsuko Uchida had played Mozart’s C-major (K.467) Piano Concerto Thursday through Saturday. The rest of the program, which was led by Roberto Abbado (the great Claudio’s nephew), remained the same: the US premiere of Hans Werner Henze’s edgy but dreary year-old Scorribanda Sinfonica, sopra la tomba di una Maratona ("Symphonic Raid on the Tomb of a Marathon," a reference to Henze’s recyling music from his 1955 dance-marathon ballet) and Rachmaninov’s not-often-performed (and just as well) Third Symphony.

Jackiw is a patrician player — his incomparable technique and radiant tone are not compromised by any emotive display. He barely moves. And he looked elegant in his unwrinkled black silk Chinese jacket. The Mendelssohn was warmer than his Sibelius concerto with Benjamin Zander and the Boston Philharmonic last year, and the audience rose to cheer him at the end. Better this restraint than the self-dramatizing writhing and hair tossing you see in many young violinists (and some older ones, too).

But the best performances of Mendelssohn’s irresistible, irrepressible masterpiece (which he completed at a ripe old 35) sing out with ardent discovery. Jackiw didn’t exactly play it by rote, but he did convey the sense that he knew before he started where every note would be placed. "He’s like an electric train," a friend remarked. He may be as technically gifted as the young Yo-Yo Ma, but right now he’s connecting to the notes more than to the music. I wish he’d sit down with Joseph Szigeti’s miraculous 1933 recording under Thomas Beecham (on Pearl — a rare omission from the BSO program booklet’s list of significant discs); it’s actually about human feelings — love and unbridled joy and yearning nostalgia — and not just beautiful playing.

Jackiw was not entirely responsible for what was lacking. Given Abbado’s utterly pedestrian, lackluster accompaniment, it would have been hard for anyone to breathe life into this.

Abbado delivered a tighter performance of the windy Rachmaninov than the flabby one André Previn led in 1998. Previn’s usual rhythmic limpness characterized two-thirds of his latest BSO concert: a gray Haydn 102nd Symphony (plodding when it should sparkle and crackle) and a mushy, inert Mozart Sinfonia Concertante (BSO concertmaster Malcolm Lowe and principal violist Steven Ansell in the solo parts) — Mozart’s greatest, most inventive concerto for string instruments. The heavenly Andante was surely a little more like a lullaby than Mozart intended.

I was dreading the remaining work, Beethoven’s Symphony No. 7, which I’ve heard in too many good performances. But from the haunting slow introduction, with oboist John Ferillo’s imaginative phrasing making me perk up and pay attention, to the finale’s manic dance, Previn brought it delightfully to life. Maybe because the dancing rhythms are already built into this symphony, or because the players know it so well they don’t even need a conductor, or because Previn got the quiet passages so soft that Beethoven’s periodic explosions were truly startling (though the balances were so tipped to the bottom of the scale that detail was often reduced to a blurry growl), or because Previn has some genuine feeling for this piece — for any or all of these reasons, it worked. Not the most memorable version, but at least one to keep you awake.

SUSAN DAVENNY WYNER has rhythm to spare, so composer Yehudi Wyner was lucky to have his wife lead her New England String Ensemble in the premiere of his Tuscan Triptych: Echoes of Hannibal, an anguished, sometimes violent, but mostly elegiac expansion of the 1985 string quartet he wrote during a year’s stay in Tuscany — near where Hannibal defeated the Romans. The title, which came last, seems misleading. The first two movements are much shorter than the last, and they have within them sharply contrasting sections, so "triptych" suggests the wrong proportions. Throughout, what I kept picturing was not an invading army but the movement of a mind at work, searching, hovering over a landscape — or a truth — then finally getting inside it, exploring it from within. I’d call it something like Frost’s "To Earthward."

Lucky too were Handel with a noble and nimble D-major Concerto Grosso (Opus 6 No. 10) and Chausson with an eloquent rendition of his Concert in D for Violin, Piano, and String Quartet (here a string orchestra), Irina Muresanu’s voluptuous violin being the perfect partner for Ya-Fei Chuang’s iridescent pianism.