Despite many years and thousands of pounds spent on research, science still cannot reliably predict whether a material will crystallise, what solvents it will crystallise from and what the final structure will look like. There are over quarter of a million structures in the Cambridge Structural Database and much can be learnt from these. Systematic examination of characteristic materials can also give key insight into the process of crystallisation. Understanding how a material behaves in response to external stimulus (e.g. change in temperature) can also help us to understand how molecules talk to each other.