The book is intended for UG, PG, and research scholars as a research guide on the method used to enhance the solubility, dissolution, and bioavailability of BSC class II drugs. BCS class II drugs generally have low oral bioavailability due to poor water solubility. The solid dispersions were prepared by using various hydrophilic carriers in different ratios. The molecular dispersion of the drug in the carrier may change the solid-state property of the drug from crystalline to amorphous form. The improvement in drug dissolution can be achieved by reducing particle size and increasing surface area, improved wetting of the particles, and particles with high porosity. The solid dispersion method was suitable to improve the solubility, dissolution, and bioavailability of BCS class II drugs.