Crooning is a 20th century style of singing made possible by the invention of microphones and amplifiers, which allowed the crooner to sing in a much softer, quieter, more intimate style.

Its popularity peaked during the 1920's to 1950's with the advent of radio and electric recording allowing crooners to be heard by millions.
Who are the best known crooners of all time? Crooners were almost by definition entirely male. 

As the decades passed, crooning began to fall out of fashion and was written off by many as a fad. 

It was ultimately dethroned by a new style of music in the 1950's, rock and roll. Today, modern crooners are categorized as "adult contemporary" or "easy listening".

Crooner is an American epithet given primarily to male singers of jazz standards, mostly from the Great American Songbook, backed by either a full orchestra, a big band or a piano. 

Originally, it was an ironic term denoting a sentimental singing style made possible by the use of microphones. Some performers, such as Russ Columbo, did not accept the term.

Frank Sinatra once said that he did not consider himself or Bing Crosby "crooners".