This collection of Case Studies has been put together in order to illustrate how interesting mathematics can be used effectively in a wide variety of fields. The Case Studies have been chosen from problems brought to ESGIs supported by MI-NET or carried out during an STSM funded by MI-NET. The 21 Case Studies span a diverse range of industrial sectors and utilize a wide variety of mathematical methodologies. The ESGI Case Studies come from nine countries across Europe and involve five small–medium enterprises (SMEs), four Large Enterprises (LEs) and one governmental unit. The 10 STSM Case Studies capture cutting-edge research collaborations between 11 countries. We have also included a Case Study on the modelling of coffee making from a one-day Industrial Workshop.