In the last few years, Knowledge-Aware Recommender Systems (KARSs) got an increasing interest in the community thanks to their ability at encoding diverse and heterogeneous data sources, both structured (such as knowledge graphs) and unstructured (such as plain text). Indeed, as shown by several shreds of evidence, thanks to the combination of such information, KARSs are able to provide competitive performances in several scenarios. In particular, state-of-the-art KARSs leverage the current wave of deep learning and are able to process and exploit large corpora of information that provide complementary and useful characteristics of the items, including knowledge graphs, descriptive properties, reviews, text, and multimedia content. The objective of my Ph.D. is to investigate methods to design and develop knowledge-aware recommendation models based on the merging of heterogeneous embeddings. Based on the combination of diverse information sources, I plan to develop novel models able to provide accurate, fair, and explainable recommendations.