Worldwide efforts are underway to create a revolutionary and energy-efficient information technology in which digital data are represented by the spin orientation of electrons. Implementing spin functionality in silicon, the mainstream semiconductor, has the potential to create broad impact. Remarkable advances in the creation and control of spin polarization in silicon have therefore generated much excitement. This lecture describes spintronics and spin caloritronics in silicon-based devices. It presents the key developments and achievements, our current understanding, as well as the unsolved puzzles and challenges that stimulate researchers in the field.