The best things in life are free, and these certainly include the weekly concerts at the National Gallery of Art. Yesterday's piano recital by Elizabeth Mruk-Stevens filled the East Garden Court with the elegance and charm of Haydn, Schubert, Webern and Given. It was a fine concert.

Mruk-Stevens has a good sense of the classical style, often achieving exuberance and passion without indulging in unidiomatic mannerisms. Her fast passages were particularly impressive in their clear articulation, and the restraint of Schubert's "Moments Musicaux" was refreshing. Most rewarding was Haydn's Sonata in E-flat Major, Hob. XVI/52. There was eloquence and breeding in her hands. Strong measures were never cloudy and rests were always patient.

She was splendid in "Variations for Piano" by Webern. This 1935 jewel can still sound like a kitten walking on the keyboard; or it can be illogical and cold. Not here. From the first bar Mruk-Stevens understood the music's uncertain steps toward elusive beauty, bringing the most to the danceable second variation and using the pedal just enough to sustain tension without altering the line.

Webern's diamonds were followed by some delightful rhinestones. "A Midsummer Waltz" by Eric Given, a composer who lives in Maryland, was unassuming and light. It could have been written by Gottschalk in one of his European moods. There was a feeling of unembarrassed romance in the long opening trill, then the music exploded into brief bursts of melodies in 3/4 time, all very simple and very likable.