This book provides some important aspects of acetic acid, especially those concerning its recent use and applications, including the fermentation process of ethanol with acetic acid bacteria, its use in meat preservation, medicinal effects of acetic acid, as well as health and safety considerations. Other aspects include the properties of auxins, an important category of acetic acids influencing a number of physiological and developmental processes in plants, the characterisation of the synthesis, structural and vibrational properties of three quinoline acetic acid derivatives with potential biological activities and the use of acetic acid in food preparation/production and the co-production of vinegar and electricity through fermentation.