Bioinformatics and cheminformatics are scientific disciplines that have evolved in recent decades at the interface between chemistry, biology, and computer science. In many areas of chemistry, biology, and materials science, the huge amount of data and information produced by robotic high-throughput assays and micro-array technologies can only be processed and analysed using computational techniques. Predictive informatics methods employ statistical techniques to mine this data for hidden correlations and to retrieve molecules, genes or patterns with specific properties or desirable biological activities from large databases. Furthermore, many of these problems are so complex that novel approaches utilizing solutions based on informatics methods are necessary. Informatics methods have been especially valuable in drug design and development, but are also increasingly employed in several other disciplines which are governed by the science of complex systems. This calls for an inter-disciplinary approach to the study of these problems.