Significance of the titleEdit
The book is named after the book in the novel, "a cryptographer's bible" that contains much about cryptography and cryptanalysis. The name is a play on "Necronomicon", the title of a book mentioned in a number of horror stories written by H. P. Lovecraft. Stephenson claims to have chosen "Cryptonomicon" to make the book sound like something a 17th-century scholar would be likely to have.
In the CycleEdit
James Wilkins is the author of a book called Cryptonomicon, which is a manual for cryptography, referenced in various places within the Cycle. In seeming disgust for having contributed to a method for concealing knowledge, Wilkins attempts to create a Philosophickal Language to disseminate it instead. Nevertheless, cryptography and secret messages play an important role throughout the Cycle. In real history, Wilkins wrote a manual of cryptography (not using the name Cryptonomicon) as well as attempting to create a universal language, although not at the times depicted in the Cycle.
Spoiler Warning: A driving theme of the Baroque Cycle is its historically accurate account of Sir Isaac Newton as an alchemist and as Britain's Master of the Mint. The name of the Baroque Cycle's final book, System of the World, is a reference to another historically accurate theme, the development of the monetary system in use today. The book explicitly tells us that this fledgeling monetary system may have some then-unknown, irreconcilable, and ultimately fatal flaw. The book implicitly tells us that alchemy works: you can turn base metals to gold, and you can live forever. The covers of the Baroque Cycle's three books relate to this alchemical theme. Their colors -- (quick)silver, bronze, and gold -- reflect the alchemists' belief that metal ores "age," with lead being the youngest and basest metal and gold being the oldest and most valuable. Quicksilver (another name for mercury, which was believed to be a necessary ingredient in alchemy as well as being named after the Roman god of commerce), bronze and gold are progressively more valuable metals. The cover of Cryptonomicon, a book that concerns itself with the descendants of the Baroque Cycle's characters and with the descendant of its monetary system, is black -- the color of lead. Think Stephenson is telling us something about that system's fatal flaw?