{mosimage}Lfi, or Low Frequency Instrument, is ready. It is the best radio-receiver in the world to study the tiny microwave ripples of the primordial universe. It has taken more than ten years of hard work to design, develop, and build it. An activity which has been carried out mainly in Italy, under the leadership of Nazzareno Mandolesi (director of Iasf-Bo), Lfi’s Principal Investigator. In 2008 Lfi, together with its hi-freq mate Hfi, will be flying on the Esa satellite Planck towards the Second lagrangian point, 1.5 million kilometres away from the Earth. Mission purpose: to produce the most detailed and accurate map of the baby-universe, just 370.000 years after the Big Bang.