He was listed in the 1980 Guinness Book of Records as the "world's highest tenor" for having hit and sustained an A above high C for 3.8 seconds at The Town Hall in New York City on September 12, 1972.
Zucker and his audience (who participated by means of comments called in during musical segments) were highly focused on great singers and singing technique.
The articles focus on Gioachino Rossini, castratos and florid singing; the David family of tenors; Andrea Nozzari; Giovanni Battista Rubini; Gilbert Duprez; and the high C "from the chest."
Zucker and his mother, soprano Rosina Wolf, claim to be the last in a line of singers using the method of singing style taught by Giovanni Battista Rubini.
The critic Donal Henahan wrote in The New York Times, reviewing Zucker in a performance of Bellini's opera Adelson e Salvini, that his high notes were like "the scratching of a fingernail on a blackboard."