"Stars like our Sun and planets like our Earth form in dense regions within interstellar molecular clouds, called pre-stellar cores (PSCs). PSCs provide the initial conditions in the process of star and planet formation, but large uncertainties exist concerning basic astrophysical processes and parameters, such as surface chemistry, the cosmic-ray ionization rate, the H2 ortho-to-para ratio, the abundance of atomic Oxygen and ""metals"". In current models, these parameters/processes are typically fixed to some ""canonical"" values and variations across PSCs are neglected. With the new generation of telescopes and the advances in radiative transfer and dynamical/chemical modelling, the time has now come to develop theoretical models without highly uncertain parameters.PCSs are dark, cold and quiescent. They are the simplest units in the process of star formation. Thus, they provide a unique opportunity for the study of fundamental astrophysical processes in a ""calm"" environment, just before the battering of the protostellar ""storm"". For this reason, PSCs can be used as ideal laboratories to refine our understanding of how stars and planets form. With this advanced grant fellowship, I plan to connect state of the art dynamical and chemical models and test them against detailed observations of prototypical PCSs to first deliver parameters and processes that are needed to understand basic physical mechanisms. I will then explore in detail the formation, evolution and physical/chemical structure of PSCs in different environments. Finally, with the help of ALMA data, I will focus on the central few thousands AU and study the first steps toward the formation and early evolution of proto-planetary disks (PPDs).This is sorely needed to enable us to understand the initial conditions in the process of star and planet formation and to link PSCs with PPDs, currently studied by different communities, with the ultimate aim of understanding our chemical/physical heritage."