Here is a brief overview—hyperlinks included—of those color books by the International Union of Pure and Applied Chemistry (IUPAC) that have accessible online versions [1-3]:
The interactive Gold Book at goldbook.iupac.org, and the PDF version Compendium of Chemical Terminology at goldbook.iupac.org/PDF/goldbook.pdf. It is not named for the color or chemical element gold, but to honor the chemist Victor Gold (1922-1985), who initiated its first edition [4,5].
The Green Book: Quantities, Units and Symbols in Physical Chemistry [http://www.iupac.org/fileadmin/user_upload/publications/e-resources/ONLINE-IUPAC-GB3-2ndPrinting-Online-Sep2012.pdf]
The Blue Book: Nomenclature of Organic Chemistry by Advanced Chemistry Development (ACD) [acdlabs.com/iupac/nomenclature]
The Purple Book: Compendium of Polymer Terminology and Nomenclature [www.iupac.org/fileadmin/user_upload/publications/e-resources/ONLINE-IUPAC-PB2-Online-June2014.pdf]
The Orange Book: Compendium of Analytical Nomenclature (website by David S. Moore) [http://iupac.org/publications/analytical_compendium/]
The Red Book: Nomenclature of Inorganic Chemistry [www.iupac.org/fileadmin/user_upload/databases/Red_Book_2005.pdf]
The “White Book”: Biochemical Nomenclature and Related Documents [www.chem.qmul.ac.uk/iupac/bibliog/white.html]
The Silver Book: Clinical Chemistry is currently under revision (future status of Web availability unknown) [www.iupac.org/nc/home/projects/project-db/project-details.html?tx_wfqbe_pi1[project_nr]=2007-033-3-700]
Organizationally, the color code gold (in memory of Victor Gold) stands for the combined glossary. As you may have realized by reading the compendium titles, the other colors refer to sub-disciplines or branches of chemistry: green for physical, blue for organic, purple for macromolecular, orange for analytical, red for inorganic, “white” for “biochemical” and silver for clinical .
Mark Borkum and Jeremy Frey argue the case for Web-based, machine-accessible representations of these and other IUPAC publications to make them available for reuse by software developers . Further, they urge IUPAC to take immediate measures in promoting a “cohesive vision of chemical terminology, nomenclature and ontology on the Web” by acknowledging and visionarily involving interdisciplinary chemists and software engineers:
There are many fine examples of “chemist-ware” on the Web, but their developers represent an absolutely tiny fraction of the world's chemists, who are presently unable to fully express themselves.
Keyterms: cheminformatics, polymer informatics, computer science, e-science infrastructure, standardization, chemical compendia, online resources, open software architecture, open-source mantra.
 Mark I. Borkum and Jeremy G. Frey: What's in a Name? Quite a Lot, as it Happens! Chemistry International March-April 2015, pp. 7-9 [www.degruyter.com/view/j/ci.2015.37.issue-2/ci-2015-0231/ci-2015-0231.xml].
 IUPAC: Nomenclature and Terminology (including IUPAC color books) [www.iupac.org/home/publications/e-resources/nomenclature-and-terminology.html].
 Wikipedia: IUPAC book [en.wikipedia.org/wiki/IUPAC_book].
 W. J. Albery: Victor Gold, 29 June 1922 - 29 September 1985. Biographical Memoirs of Fellows of the Royal Society December 1987, 33, 263 ff. DOI: http://dx.doi.org/10.1098/rsbm.1987.0010.
 Hawaii Book Library: Victor Gold (Chemist) [www.hawaiilibrary.net/article/whebn0022605991/victor%20gold%20%28chemist%29].
 International Union of Pure and Applied Chemistry: Nomenclature Books [www.chem.qmul.ac.uk/iupac/bibliog/books.html].