In Rubinstein's vast discography the music of brahms is second in prominence only to that of chopin. That Brahms was a lifelong enthusiasm of the pianist is in at least one sense not at all surprising, since Rubinstein's sponsor and mentor when he undertook his studies in Berlin at the age of ten was none other than Joseph Joachim. The illustrious violinist, who had been Brahms' closest associate, had founded the Hochschule für Musik in Berlin in 1868, and came to regard pedagogy as being equal in importance to his more visible activity as soloist, chamber-music player (founder and leader of the Joachim Quartet), composer and conductor. Rubinstein's mother first brought her son to Joachim when the boy was only four; at that time, Joachim's advice was to get the boy the finest instruction available in his hometown (Lodz) and observe his progress. Six years later, in the very year of Brahms' death, the now ten-year-old Rubinstein was brought to Berlin again by his mother and, following some disheartening auditions for various other potential teachers, he was heard by Joachim for the second time. On this occasion, Joachim was sufficiently impressed to take positive action. Since the boy was too young to be registered at the Hochschule, he arranged for him to be taught privately by members of its faculty, chief among them being the highly respected piano teacher Karl Heinrich Barth. Joachim rounded up some sponsors to cover the young Rubinstein's living expenses, contributing to the fund himself; he monitored the lad's progress with Barth, gave him every encouragement, conducted his first public concerto performance— and of course gave him the enormous benefit of his own long acquaintance with and abiding love for the music of Brahms. While Joachim was a truly unique and authoritative source of Brahms lore, he was by no means the sole instigator of Rubinstein's enthusiasm for the music of that composer. Through Joachim and his other sponsors, the lad had entrée to the homes of various well-to-do Berlin families. Through a contact of his own, from Lodz, he was welcomed into the home of a banker named Hahn, whose wife was herself a pianist; and it was there that Rubinstein became, as he put it later in a memoir, obsessed with Brahms' chamber music when he heard his hostess and some friends perform the piano quartets in A major and C minor. Joachim subsequently introduced him to pianists who had known Brahms or had been pupils of Clara Schumann, and whose own performances further intensified his response to Brahms' keyboard works. The "obsession" never diminished over the years. The B-Flat Concerto became a fixture of Rubinstein's career early on, and the D minor was in his active repertory till the very end. In his discography there are numerous Brahmsian signposts: the first piece he recorded under his initial contract to HMV was a Brahms Capriccio; the first extended work he recorded was the B-Flat Concerto; his earliest recordings of chamber music, also among those pre-war undertakings for HMV, were the three Brahms performances preserved on the present disc. After recording these in 1932 and 1936. Rubinstein made a recording of the Franck Violin Sonata in 1937 with Jascha Heifetz, with whom he was to embark on a more widely noted series of chamber music recordings for years later: the now legendary ones of trios with the unforgettable cellist Emanuel Feuermann—which again began with Brahms (in this case the B-MajorTrio, Op. 8). The Pro Arte Quartet, a Belgian group founded in IQI2, was one of the most respected chamber-music ensembles of its time, and maintained its original membership (violinists Alphonse Onnou and Laurent Halleux, violist Germain Prévost and cellist Robert Maas) until Onnou's death in 1940 in Wisconsin, where the group had settled at the beginning of World War II. Several of the outstanding instrumentalists of the prewar era performed and recorded with the Pro Arte, whose recorded legacy includes pioneering versions of works by Debussy, Ravel and Bloch, collaborations with Artur Schnabel in Mozart and Schubert, and an incomplete but distinguished survey of Haydn's quartets. Rubinstein would record all three of the Brahms piano quartets with members of the Guarneri Quartet in 1967. The two duo sonata recordings here represent longer and more significant associations for Rubinstein, both personally and professionally. He first met violinist Paul (Pawel) Kochanski, only a few months younger than himself, in Warsaw, when he returned to Poland from Berlin in 1904. They shared numerous enthusiasms and similar experiences; Kochanski, a native of Odessa, had studied there with Emil Mlynarski (later Rubinstein's father-in-law), who brought him to Warsaw at the age of 14 to be concertmaster of his new orchestra, the Philharmonic, and there he raised funds to send Kochanski to Belgium, where a first prize at the Brussels Conservatory started him on his life as a soloist. He and Rubinstein later joined forces with the composer Karol Szymanowski and the composer/conductor Grzegorz Fitelberg to form the alliance "Young Poland, " under the sponsorships of Prince Lubomirski. Rubinstein and Kochanski remained close friends until the violinist's death in New York in 1934. and in the following year Rubinstein named his first-born son after him; this was their only recording together. In i960 Rubinstein recorded the three Brahms violin sonatas with his compatriot Henryk Szeryng. This 1936 recording of Brahms' E-Minor Sonata with Gregor Piatigorsky initiated a partnership that was to be resumed more than a dozen years later in the United States, when Rubinstein and Piatigorsky formed a trio with Jascha Heifetz (Feuermann having died a few months after his 1941 recordings with Heifetz and Rubinstein). The Rubinstein -Heifetz-Piatigorsky Trio made some festival appearances in 1949 and '50 and made three stunning recordings in the latter year, but soon disbanded because of differences between Rubinstein and Heifetz. Each of those two, however, continued his friendship with Piatigorsky; he and Heifetz went on to create the Heifetz-Piatigorsky Concerts, which flourished in Los Angeles and on records for years; he and Rubinstein re-recorded the E-minor Sonata in 1966, and at that time recorded Brahms' later one in F Major (Op. 99) as well. —Richard Freed Richard Freed is a distinguished music critic, annotator and broadcaster.