There have been remarkable breakthroughs in the design of lanthanide single molecule magnets, with huge energy barriers for magnetic relaxation reported[1-4]anda major advance in the temperature at which magnetic hysteresis can be observed.[2-4]However, it is reasonable to state that why we now have a good understanding of the static electronic structure and how we can control the size of the energy barrier through imposing a strongly axial crystal field,[1]we do notunderstand the dynamic behaviour and how the lanthanide magnetisation is lost and how we can control relaxation mechanisms beyond Orbach relaxation. Preliminary studies of relaxation will be discussed on a range of lanthanide single molecule magnets.[5]This may also cover the role of Ln...Ln interactions.[6]