Phase-change Material based heat sinks and associated optimization remains a topic of great interest, as evident from the increasing number of citations and new applications and miniaturization. Often the multi objective perspective of such heat sinks is ignored. This book introduces the readers to the PCM based heat sinks and Multi objective optimization. The authors have also included interesting in house experimental results on the "Rotating heat sinks" which is a first of a kind work. Useful to budding thermal researchers and practicing engineers in the field, this book is also a great start for students to understand the cooling applications in electronics and an asset to every library in a technical university. Since this book not only gives a critical review of the state of the art but also presents the authors' own results. The book will encourage, motivate and let the reader consider pursuing a research career in electronic cooling technologies.