Guest editors’ introduction: special issue of selected papers from ECML PKDD 2009.

The article discusses the papers presented at the European Conference on Machine Learning (ECML) and the European Conference on Principles of Data Mining and Knowledge Discovery (PKDD). It notes that the papers are related to machine learning and data mining communities including "Sparse kernel SVMs via cutting-plane training," which features the state of the art efficiency in inducting and evaluating support vector machine (SVM) models. Other topics of the papers are also presented.