Introduction ============ Kale-Linear is a Python library for non-deep, knowledge-aware machine learning from multiple sources, domains, or views. It provides NumPy-based implementations of transfer learning, domain adaptation, manifold regularization, and group-aware linear learning methods with a scikit-learn style API. The package is part of the PyKale ecosystem and focuses on classical linear and kernel methods that are useful when data are structured by domain labels, covariates, side information, or unlabeled target samples. Main Features ------------- * Transformer models for learning feature embeddings: MPCA, TCA, JDA, BDA, and MIDA. * Estimator models for classification and adaptation: LapSVM, LapRLS, ARSVM, ARRLS, CoIRSVM, CoIRLS, and GSDA. * NumPy-compatible inputs and outputs. * scikit-learn style ``fit``, ``transform``, ``predict``, ``fit_transform``, and ``fit_predict`` workflows where applicable. * Optional covariate encoding for categorical domain or group labels.