Picture a voice recital in which the singer gets totally lost, the pianist leaves the stage in disgust, and the singer, not noticing, breaks up into hysterical and embarrassed laughter. It happened just that way -- intentionally -- Saturday evening at the Library of Congress in a wonderful and imaginative concert of 20th-century music performed by bass baritone Lieuwe Visser and pianist Robert Nasveld. The piece was Nasveld's own work, "Imaginations I" (1978), which along with the humor was a moving expression of the universally feared "performance nightmare."

The concert opened with Josef Matthias Hauer's Ho lderlin-Lieder, Op. 21 (1922), settings of ecstatically romantic poems in Hauer's own unique 12-tone system. In these largely tonal works, the singer must create his own rhythm and dynamics -- Hauer supplies only the pitches. Visser was brilliant; by creatively using the word rhythms he constructed expressive recitatives linked by evocative chord clusters from the piano.

Ton Bruyne`l's "Denk mal das Denkmal" ("Just Remember the Memorial") for sound track and bass baritone was a sober affirmation of living in the face of past wars, present political tensions and threats of future wars, and was filled with symbols from Revelation, Germany's Nazi past and Schubert's "Erlking."

Visser met the demands of his challenging program with ease and amazing vocal variety, from the deep, rich tones in Stockhausen's complex "Tierkreis," which expressed the signs of the zodiac, to the Sprechstimme and falsetto of John Cage's settings of texts by James Joyce.