Alkaloids are naturally occurring chemical compounds containing basic nitrogen atoms. The name derives from the word alkaline and is used to describe any nitrogen-containing base and organic compound. They often have pharmacological effects and are used as medications, as recreational drugs, or in entheogenic rituals. This book presents current research in the study of alkaloids including a tropane alkaloid called scopolamine employed in medicine as an anticholinergic; quaternary benzo(c) phenantridine alkaloids; pilocarpine alkaloids used in the treatment of glaucoma; ergot alkaloids and their use in ocular pharmacology and others.