People who are working on data science and machine learning in Finance. The process of finding "truths" in Finance has now very much shifted from the neural network of traders minds to data science / machine learning processes. Data Science in Finance has much in common with Data Science in other tech fields. We deal with new data being much more important than old data, yet there are common themes that persist. 1. What we care about is future performance 2. We don't have "future data". We only have historical data. 3. Not every aspect of past data is equally likely to occur tomorrow. Therein lies the challenge!