diff --git a/features/baseline.py b/features/baseline.py
new file mode 100644
index 0000000..66c6c4b
--- /dev/null
+++ b/features/baseline.py
@@ -0,0 +1,12 @@
+from collections.abc import Collection
+
+import pandas as pd
+
+def read_baseline(paths: Collection) -> pd.DataFrame:
+    #TODO Read CSV files and concat them.
+    pass
+
+
+def preprocess_baseline(df_baseline_from_csv: pd.DataFrame) -> pd.DataFrame:
+    #TODO Translate columns, calculate age.
+    pass