**Preface to "Symmetric and Asymmetric Distributions"**

This Special Issue contains nine chapters selected after a comprehensive peer review process. Each chapter exclusively adheres to the topic specified in this Special Issue. The Associate Editor wants to especially thank all the authors who made this Special Issue possible, and all the anonymous reviewers for their altruistic effort and help in reviewing and for their excellent suggestions and critical reviews of the submitted manuscripts. All the chapters are written in the format of a research article for scholarly journals, i.e., title, abstract, and development, with an extensive bibliography at the end of the paper. All of them include real applications that will undoubtedly be useful for other researchers and graduate students who conduct similar research. I express my gratitude to MPDI for publishing this book, to Ms. Celina Si, Section Managing Editor, for her work and patience, and last but not least to my family for their support and cooperation.

> **Emilio Gomez ´** -**D´eniz** *Editor*
