A view of life as based on organic chemistry neglects the importance of all the elements that are traditionally in the purview of inorganic chemistry. Transition metals from the first series (Mn, Fe, Co, Ni, Cu, Zn) are critical for life as cofactors in thousands of proteins. This symposium focuses on how cells select transition metal ions and control their concentrations. Metal ion selection includes chemical principles, but also biochemical principles that solve issues how highly competitive metal ions can be selected against unfavourable concentration gradients. The symposium will open with views from Prof. RJP Williams (Inorganic 91AV, Oxford University), one of the founders of the field of inorganic biochemistry and the originator of the Irving-Williams series, a now classical concept that describes the stability of coordination compounds of the transition metal series.