The listing is two books focused on the study of symbols and signs:

• Signs & Symbols: The Complete Encyclopedia of Signs & Symbols by Mark O'Connell and Raje Airey: This book is described as an identification and analysis of the visual vocabulary that formulates thoughts and dictates reactions to the world. It aims to interpret the unconscious codes and secret languages that shape ancient emotions. The encyclopedia contains over 1600 visual symbols, including photographs, fine art paintings, and line illustrations, accompanied by authoritative in-depth commentary, definitions, and explanations.

• Symbols, Signs & Signets: A Pictorial Treasury with Over 1350 Illustrations by Ernst Lehner: This work is a comprehensive pictorial treasury of signs, seals, and symbols from various historical and cultural contexts, including Babylonia, Egypt, Greece, Rome, Germanic, Byzantine, Renaissance, Aztec, Hindu, Islamic, Chinese, and Japanese cultures. It covers a wide range of categories such as astrological, alchemical, magical, early Christian, masonic, and heraldic symbols, crests, goldsmiths' marks, and watermarks, all reproduced from authentic sources. Lehner is noted as one of the world's foremost collectors of pictorial symbols, with illustrations rendered from rare sources.