The long journey to the laser and its rapid development after 1960

The laser, a fascinating new light source with numerous applications in our daily life was first realized some 50 years ago. The principle was initiated in 1916 when Einstein introduced a new concept of radiation-matter-interaction known today as stimulated emission of electromagnetic radiation. It took nearly 40 years before a first practical device based on stimulated emission - the maser - was realized for microwaves in 1954. In 1960, the first laser was operated in the visible. This historical note reports on the way to the laser with its climax in 1960. The subsequent explosive development of new lasers and of fundamental applications is shortly reviewed in the second part of the paper.