Early solidification experiments in immiscible alloy systems almost immediately led to conflicting findings between investigators. Investigations revealed that several factors usually considered unimportant, especially the interfacial energy relationships between phases, could have a dramatic influence on the types of microstructures produced in immiscible alloy systems. During the 1980s, work concentrated on the influence interfacial energy on microstructure. However, some findings raised new questions. In the mid 1990s and continuing through today, most efforts have focused on modeling the monotectic growth process and on obtaining steady state coupled growth conditions in hypermonotectic alloys. This paper focuses on some of the advances that have been made to date in understanding solidification in immiscible alloy systems and some of the questions that remain to be answered.