Innovation and technical change is central to long term economic growth but it is treated very differently in economic theories. In a comparative manner this course presents technical change within major theoretical approaches: neoclassical growth models, endogenous growth models and evolutionary structural models. Particular attention is given to an economic historical model combined with a spatial theoretical framework of regional trajectories of growth. The model is based upon complementarities around innovations forming development blocks that are driving processes of structural change. Thus, the interplay between innovations, economic transformation and economic growth is studied with an emphasis on major carrier branches both historically and in contemporary times. Innovations are analysed in relation to variations over time in, e.g., relative prices, entrepreneurial activity, investments, labour demand and employment. It is shown how this, at an aggregate level, shows up in phases of spatial convergence and divergence, respectively.