Circular dichroism (CD) refers to the differential absorption of left and right circularly polarised light. This phenomenon is exhibited in the absorption bands of optically active chiral molecules. CD spectroscopy has a wide range of applications in many different fields. Most notably, UV CD is used to investigate the secondary structure of proteins. This book presents current research in the study of circular dichroism, including a study of the peculiarities of the circular dichroism spectra of double-stranded DNA cholesteric liquid-crystalline dispersions; magnetic circular dichroism in electron microscopy; and, the application of CD spectroscopy for short peptides such as the human immunodeficiency virus type 1 (HIV-1) inhibitor.