This book is divided into two sections. Section One covers the authors' work on the synthesis and characteristics of the various carbon nanofibers and microcoils using chemical vapor deposition and electrospun technologies. This section includes Chapters One through Four. Chapter One is an introductory chapter which presents synthesis, properties and analysis of carbon nanofibers and microcoils prepared by chemical vapor deposition and electrospun technologies. Chapter Two introduces information for approaching electrospun carbon nanofibers (ECNFs) with superior mechanical strength from aligned and stretched polyacrylonitrile (PAN) copolymer nanofibers possessing high degrees of morphological and structural perfection. Chapter Three investigates the in-situ and ex-situ processes for the formation of geometrically controlled carbon microcoils and the practical application of carbon microcoils to the various nano/micro electronic or mechanical devices. Chapter Four discusses the synthesis and various characterizations of carbon nanofibers synthesized by catalytic chemical vapor deposition of halogenated hydrocarbons. Section Two deals with the recent advances in materials synthesis and characterization of carbon nanofibers and their applications such as Li secondary batteries, supercapacitors and heavy metal remediation in ground and wastewater. This section includes chapter Five through Ten. Chapter Five presents preparation and characterization of carbon nanofibers (CNFs), CNFs-Si, and CNFs-(PC)Si composites synthesized by the Chemical Vapor Deposition (CVD) method using transition metal catalysts and applications to anode materials of Li secondary batteries. Chapter Six introduces a synthesis and characterization of carbon nanofibers and Si/carbon nanofiber composites based on Ni and Mo catalysts prepared for the anode material of Li secondary batteries. Chapter Seven discusses the electrophoretic deposition of Ni and Cu catalysts on C-fiber textiles for the growth of carbon nanofibers and coating of silica by the hydrolysis of tetraethyl orthosilicate on carbon nanofibers, and finally applications to the anode materials for Li secondary batteries. Chapter Eight presents synthesis and characterization of transition metal coated carbon nanofibers on Ni foam via CVD followed by a dipping method and electrochemical performance as anode materials for Li secondary batteries. Chapter Nine introduces a design of hierarchical porous carbon materials containing various metal oxides as an electrode material for high-performance supercapacitors. Chapter Ten discusses an innovative carbon nanofibrous composite material prepared by the electrospun method and its application for efficient heavy metal pollutant remediation in contaminated groundwater as well as in wastewater treatment.