Health informatics is an interdisciplinary field tracing its roots from various other fields, and it has gone through various transformations including various names. This chapter explores the evolution of the field of health informatics by emphasizing on significant developments in each decade starting from its early origins to the current era. This chapter presents how the field has evolved throughout this timeline, especially by connecting various developments in each decade to the next, and ultimately how it has evolved to its current role in transforming the delivery of healthcare.