Maybe because he's one of classical music's durable triple treats as conductor, soloist and chamber player, Pinchas Zukerman is invited back to town as often as a favorite relative. If it's fall, then it must be another musical get-together with old crony Daniel Barenboim; if it's winter, then the gig must be in Symphony Center leading the Chicago Symphony Orchestra. (Both happened to Zukerman in the past few seasons.) In summer, Ravinia beckons.

Zukerman made his Ravinia Festival debut in 1970, and this time, marking his 21st season there, he had the honor of ushering in the classical portion of the Ravinia summer. On Monday, he put his enviable switch-hitting skills on display, proffering an all-Brahms program of three violin sonatas, the two (Op. 120) viola sonatas and something extra.

The bonus, which opened Monday night's concert, was the seldom-scheduled Scherzo from Brahms' youth, a movement from the composite violin sonata written in collaboration with Schumann and given as a birthday gift to Joseph Joachim, the Isaac Stern of his day who'd become Brahms' lifelong buddy. Though a piece of juvenilia that owes much to late Beethoven, its dazzling cascades of fast notes and chords hint at the impetuous moments in the great piano quartets to come. Zukerman and pianist Marc Neikrug, a longtime partner, played it with verve; yet they didn't quite click together, and Zukerman's violin sounded wiry and slightly off pitch.

These problems persisted into the expansive, lyrical first movement of the Violin Sonata No. 1 in G-Major, composed by an artistically mature Brahms a quarter-century after his Scherzo experiment. Zukerman took time between movements to retune his violin and to unstick pages of the score.

A judicious move, as it turned out—their reading of the rest of the sonata was measurably better though still archly romantic in the way Zukerman caressed and lingered over each phrase. The finale, in which the piano simulates rapid raindrops while the violin sings wistfully, was done with fluidity, its rumination of regrets particularly affecting.

The spotlight in the second half was on the second fiddle, as Zukerman and Neikrug embarked on the Viola Sonata in F-Minor, the first of a pair of works originally intended for the clarinet and later transposed for the viola.

Listening to this sonata is to be gripped by emotional highs and lows, passionate outbursts giving way to sorrow, which is dispelled by a country dance that leads to optimism.