n this talk, we consider the question of whether amalgams of linear groups are still linear. By analyzing matrix entries and unipotent elements, we will discuss linearity for specific algebraic "doubles" and obtain new examples of finitely generated, residually finite, non-linear groups. This includes new examples of linear groups constructed by combining together precompact groups and lattices in real semisimple Lie groups. This is joint work with Sami Douba.