A subjective review is given of the major milestones in infrared astronomy. Emphasis is placed on the survey efforts between 2 and 120 μm, the realm of the extrinsic photodetector. The historical developments in infrared astronomy and the pioneering, often marginally successful, survey attempts are put in the perspective of improving technology. Some discussion is given to the survey discoveries and how they have extended our knowledge of the infrared celestial background.