The art of feature engineering : essentials for machine learning When working with a data set a machine learning engineer might train a model but find that the results are not as good as they need. To get better results they can try to improve the model or collect more data but there is another avenue: feature engineering. The feature engineering process can help improve results by modifying the datas features to better capture the nature of the problem. This process is partly an art and partly a palette of tricks and recipes. This practical guide to feature engineering is an essential addition to any data scientists or machine learning engineers toolbox providing new ideas on how to improve the performance of a machine learning solution. Beginning with the basic concepts and techniques of feature engineering the text builds up to a unique cross domain approach that spans data on graphs texts time series and images with fully worked out case studies. Key topics include binning out of fold estimation feature selection dimensionality reduction and encoding variable length data. The full source code for the case studies is available on a companion website as Python Jupyter notebooks