Herschel will have an unprecedented view of the cold universe, bridging the gap in the spectrum between what can be observed from ground and earlier space missions of this kind. Infrared radiation can penetrate the gas and dust clouds that hide objects from optical telescopes, looking deep into star-forming regions, galactic centres and planetary systems. Cooler objects, such as tiny stars and molecular clouds, even galaxies enshrouded in dust, barely emitting optical light, are visible in the infrared. Observing in the infrared provides us with a complementary view of the universe.