In 1992, an overview was presented which summarized the status and progress made in the development of very small, “micro” heat pipes, manufactured as stand alone devices or fabricated as an integral part of silicon wafers. Since that initial review, significant advances have been made in the analysis, fabrication and testing of these devices, for use in a wide variety of applications. Following, is a review of the more recent work in this rapidly emerging field. Included is a summary of the analytical techniques developed, the various proposed methods of fabrication, and a summary of the most current test results achieved to date. Because the fundamental operating characteristics of micro heat pipes larger than 1 mm in diameter are similar to that of conventional heat pipes, this review focuses on the analysis, fabrication, and testing of micro heat pipes with characteristic dimensions of less than 500 μm. Particular emphasis is placed on research, related to the development of arrays of micro heat pipes and flat plate micro heat pipes fabricated as an integral part of semiconductor devices.