3D spectroscopy has a relatively short history. Most of the present instrument concepts were developed in the 1980s and early 1990s. During those pioneering years a great deal of work was done in optical labs in an attempt to understand how the optical fibres, microlenses and image slicers behave. Only a few groups (often formed by one or two people) worked on this topic. Communications were not very good, which explains why virtually all the groups decided to refer to this technique by a different name. So we ended up with ‘spectral imaging’, ‘bidimensional spectroscopy’, ‘integral field spectroscopy’, ‘two-dimensional spectroscopy’, ‘3D spectroscopy’, etc.

During those years it was more than doubtful whether this technique was going to be useful at all. In fact, it looked like a kind of curiosity of limited practical interest to astronomy. However, in the 1990s the first scientific results were obtained and they immediately produced a change of perception.

In the last few years investment in this type of instrumentation has been enormous. Large telescopes all around the world are now equipped with integral field units. Two instruments of the future James Webb Space Telescope will also have integral field spectroscopic capabilities, etc. Instead of being based in the optical lab trying to characterize optical fibres or micro-lenses, more effort is dedicated nowadays to refining techniques for reducing, analysing and interpreting the data obtained with a new generation of 3D spectrographs.