There is now growing interest in th

There is now growing interest in the cold sintering process (CSP) [20,21], a low temperature and energy efficient [22] sintering technique based on the uniaxial pressure of a powder mixed with a solvent in the presence of moderate heat. The densification is mainly driven by a pressure solution creep mechanism [23–25]. So far, several approaches have been used to cold sinter at least a hundred of ceramics and composites in both bulk form and with a multilayer structure [26–29]. The successful densification of these materials in a single step at temperatures which are a fraction of the conventional sintering temperature is contingent on the proper selection of transient phase chemistry. There are limited experimental resources and instrumentation available to predict or enable in situ investigations of chemical reactions within the cold sintering processing conditions. Despite such limitations, the role of chemistry in cold sintering has become undeniably apparent in both solvent selection and the proposed CSP mechanisms. In this paper, we summarize the main pathways and chemical insights that have been used to cold sinter most of the ceramics and composites. Based on several experimental investigation of distinct materials systems, we highlight the current understanding of CSP, as well as limitations and challenges that still need to be addressed.