Dr. Guttierez: Suffering from a virus, pianist Horacio Guttierez was unable to give the master class and free recital he had planned when he came to Washington last month to accept an honorary degree (doctor of music) at Catholic University. The degree was conferred in a brief ceremony, and now the master class and recital have been rescheduled: The recital is at 8 p.m. Jan. 11, and the master class is at 2 p.m. Jan. 12, both in the university's Ward Recital Hall. The recital (free and open to the public but not to critics) will include Beethoven's "Hammerklavier" Sonata, Schumann's "Humoreske" and several 20th-century works. It will be a preparation for his next Carnegie Hall performance, and he has asked that it not be reviewed.

Historically Informed Duets: The Bard record label, established by and for the Folger Consort, has until now focused on material dating from the 17th century and earlier: music of the troubadours, Elizabethan lute songs, Renaissance dances. In its latest issue, however, it has expanded its scope to include three sonatas by Beethoven: Op. 12, No. 1, in D; Op. 23 in A Minor; and Op. 30, No. 2, in C Minor. The departure is not as drastic as it might seem, however; these are, like the Folger Consort's work, "historically informed" performances, using replicas of instruments that were in use when the music was written: a gut-strung violin and a gentle-voiced fortepiano with fewer keys, a modest though crisp tone and a smaller dynamic range than a modern concert grand. Besides having a distinctive sound and a more natural balance than modern violin-piano duets, these performances are different in style from modern interpretations, partly because the players have studied performing styles of Beethoven's time, but even more because the instruments themselves, through their qualities and limitations, tell the players how the music should be handled. The performances are musically sensitive and beautifully styled.

Genaux on CD: Those who enjoyed the performance of mezzo-soprano Vivica Genaux in the Baltimore Opera's production of "La Cenerentola," or who will hear her next month in the Washington Opera's production of Handel's "Giulio Cesare," can also hear her on a new CD of Rossini songs and arias recorded in a concert last year and issued by the Ezio Pinza Council for American Singers of Opera on its Epcaso label. According to its distributor, Empire Music Group, the CD is available in many Washington record stores.

St. Nicholas and Friends: Are you secretly glad that the Christmas season is over? Tired of hearing the same old music again and again? Well, it's not quite over, if you look at it from a global perspective, and there is some Christmas music still to come that most of us will not find over-familiar. To celebrate the Russian Christmas, Slavic Mosaic, a 15-member ensemble founded in 1996, will give a concert of Slavic Christmas music next Sunday at 1:15 p.m. in St. Nicholas Russian Orthodox Cathedral, 3500 Massachusetts Ave. NW. Serge Boldireff, a choral director specializing in Russian Orthodox music, will conduct. A Russian lunch will precede the concert, beginning at noon.

O Canada: Somebody is doing something right at the Canadian Opera Company. At its annual general meeting, board President Arthur R.A. Scace reported that the company had ended its 1998-99 season with an operating surplus. This was the third year in a row that the company (now celebrating its 50th year) has ended a season with cash to spare.

Onstage: Angelina Reaux's brilliant cabaret show "Songs and Deadly Sins" ends its run at the Studio Theatre today, but those who enjoyed her interpretations of Kurt Weill can hear more of the same on her WEA-Atlantic-Teldec recording of Weill's "The Seven Deadly Sins," with Kurt Masur conducting the New York Philharmonic.

Homework: To prepare for a performance of "Martin Guerre," by the creators of "Les Miserables" and "Miss Saigon," you can find the historical background of the show in a scholarly but readable book, "The Return of Martin Guerre," by Natalie Zemon Davis and published by Harvard University Press. The 1982 French movie on the subject, starring Gerard Depardieu, is available in both VHS and DVD formats. The London cast of "Martin Guerre" has been recorded twice on CD, most recently this year in a bestseller on the DreamWorks label. This disc comprises, with some omissions, the revised (and improved) version now playing at the Kennedy Center.

"Guys and Dolls," which has just opened at Arena Stage, is one of the most popular (and one of the best) American musicals of the last 50 years. The MGM film with Marlon Brando, Jean Simmons, Frank Sinatra and Vivian Blaine is available on VHS at many video rental outlets. There are CDs of the original 1950 Broadway production (on MCA) and revivals in 1976 (Motown) and 1992 (RCA).

Noteworthy CDs: If a person wants to own just one CD of John Cage's music, the best choice might be his Sonatas and Interludes for prepared piano. In these works, the piano is transformed into a one-player keyboard percussion ensemble, with various sound-altering objects (screws, bolts, pieces of rubber or plastic) attached to the strings. The classic 1950 performance by Maro Ajemian, to whom the music is dedicated and whom Cage considered its best interpreter, has been digitally remastered and issued on CD for the first time by Composers Recordings.

Seldom heard and eminently worth hearing are the duets by Martinu, Schulhoff, Ravel and Kodaly played by Rachel Barton (violin) and Wendy Warner (cello) on a CD titled "Double Play," issued by Cedille.

Often recorded by others, but unfamiliar in their arrangement for Russian folk instruments, are most of the short pieces by Vivaldi, Bach, Tchaikovsky and others performed by the Trio Voronezh on an EMI release that bears the group's name.

A bargain-priced recording that lives up to its proud title is a two-CD set from Sony: "Broadway: The Great Original Cast Recordings." The quality falls off slightly toward the end, reflecting the decline in American musical theater, but for most of its length--from "Show Boat" to "Annie"--it is the best collection of historical Broadway performances I have heard since the much larger collection issued by the Smithsonian several years ago and no longer available.

If you missed yesterday's 24-hour musical extravaganza on PBS presenting musical greetings to the new millennium from all around the world, a fair sample is available on a Sony CD, "2000 Today: A World Symphony for the Millennium," composed and conducted by the brilliantly eclectic Chinese American composer Tan Dun. After the theme song of the event, Bob Marley's "One Love," the rest of the collection is composed by Tan Dun in a variety of styles. Performers include the Gipsy Kings, the BBC Concert Orchestra and intercultural ensembles of percussion, winds and plucked strings.

Meeting: "The widening world of chamber music" is the theme of the 22nd national conference of Chamber Music America, Jan. 14-16 in the Crowne Plaza Manhattan Hotel in New York.