We study the asset-pricing implications of technological growth in a model with "small," disembodied productivity shocks and "large," infrequent technological innovations, which are embodied into new capital vintages. The technological-adoption process leads to endogenous cycles in output and asset valuations. This process can help explain stylized asset-valuation patterns around major technological innovations. More importantly, it can help provide a unified, investment-based theory for numerous well-documented facts related to excess-return predictability. To illustrate the distinguishing features of our theory, we highlight novel implications pertaining to the joint time-series properties of consumption and excess returns.