It is well established that the material properties of alloys are directly related to the scale and distribution of their microstructural constituents. The advances and applications of metallographic techniques for the examination of solidified microstructures have proven invaluable in ascertaining these structure-property relationships. Unfortunately, many aspects of microstructural evolution can only be inferred from a post-solidification examination. The use of transparent compounds that freeze in a manner analogous to metals circumvents this problem by allowing direct and continual observation of solidification events during both transient and steady-state growth. This paper discusses the role of these compounds in promoting understanding of solidification phenomena. Examples of dendritic, eutectic, and monotectic microstructural development, pertinent to theory and practice, are presented and compared with their metal counterparts.