Asen Karastoyanov studied Flute at the Music High School in Sofia (1914-18), then he continued at the Hochschule for Musik in Berlin majoring in Flute under E. Pril and Harmony under P. Yuhn (1921-22). From 1923 to 1929 he conducted wind and symphony orchestras in Asenovgrad and Pernik. In 1930-31 he specialised in Composition at the Ecole Normale in Paris under Paul Ducas and Counterpoint at the Schola Cantorum under Paul le Flemme. In 1932 he studied Theory of Music under S. Karl-Egert and Composition with G. Rafael at the Conservatoire of Leipzig. In 1993 he returned to Bulgaria and joined the staff of the State Academy of Music as a lecturer in Theory of Music. He was promoted Full Professor in 1945.

He composed stage music; cantatas and other choral-orchestral pieces; symphonies and other works for symphony, wind, string or mandolin orchestra; chamber music; choral works; pop and dance music; he made transcriptions and orchestrations. Very popular are his five operettas. After 1944 his social songs became very popular and up to the late 1980s were among the most frequently performed works of this genre. He was awarded a lot of national prizes and distinctions.

He wrote theoretical works, textbooks and articles.

Stage music:
Ballets:
Boliar Wedding (1949, unfinished);
Brigadiers, a ballet scene (1950).

Operettas:
Ay zavala Ahmed! (Ah, What about Ahmed!) (1937, Sofia);
Rejuvenation Elixir (1938, Sofia);
Shahriar’s Wedding (1940, Sofia);
Mihail Strogov (1940, Sofia);
Bulgarians of Yore (1959, Sofia).
Three children’s operettas.

Choral-orchestral works:
Symphonic Poem “Joan Kukuzel” for tenor, mixed choir and orchestra (1939).

Cantatas:
Spring Cantata (1950);
Cantata for the Party (1954);
Transfigured Dobroudja (1955);
To the Party (1957);

Patriotic poem (1956).

Daychovo Horo, Sitno Horo (Bulgarian traditional dances) for mixed choir and orchestra.

Works for symphony orchestra:
Symphonies:
Symphony N1 Miners (1934); Symphony N2 Danube (1960); Symphony N3 Rhodope; Symphony N4 Proto-Bulgarian (1974).

Suites:
Balkan (1924); Rhodopes (1940); Midnight Sketches (1941); Youth Suite (1947); Suite from the operetta Bulgarians of Yore (1958).

Three Symphony Dances (1962).

Concertos:
Flute (1965); violoncello (1969).

Capriccio for violin and orchestra.

For wind orchestra:
Bulgarian Rhapsody (1953); 2 suites; 11 marches; 14 horo; 3 rachenitza (Editor’s note: horo and rachenitza are traditional Bulgarian dances); potpourri, etc.

For string orchestra:
Bogomil Legend (1970).

For mandolin orchestra:
Collection based on Bulgarian Folksongs (1915).

Chamber Music:
Brass Suite (1933); two quartets; two suites for flute and piano; 20 pieces for solo flute.

For piano:
Sonata (1938); two children’s pieces; Prelude; 20 polyphonic pieces, etc.

Selected books (published in Bulgarian):
Exercises in Harmony (Sofia, 1942);
Choral Conducting (Sofia, 1947);
Music Theory Essentials (Sofia, 1948);
Synopsis of Harmonic Styles with Questions and Answers (Sofia, 1948);
Instrumentation Tips (Sofia, 1948);
Melodic and Harmonic Fundamentals of the Bulgarian Folksong (S., 1950);
Counterpoint (Sofia, 1952, 1954);
Complex Counterpoint, Imitation and Canon (Sofia, 1957);
Polyphonic Harmony (Sofia, 1959), published in Russian: Polyphonic Harmony (1964).

Selected literature on him (in Bulgarian):
Pavlov, Evgeni (Klosterman). Assen Karastoyanov (Sofia, 1979).