The aim of this book is to highlight the utilization of algae for the development of useful products using environmentally friendly technologies such as supercritical fluid extraction (SFE) and accelerated solvent extraction (ASE). Each chapter is a collection of comprehensive information on the present research on algae in different applications. The primary emphasis of this book however, is concerned with the products used for agriculture. Algal extracts were presented in this book also as a biologically active component that adds value to products for humans (cosmetics), animals (pro-health supplements) and plants (plant growth biostimulants).