Introduction to Klingon Grammer was one of the books used by the crew of the USS Enterprise-A in 2293 to present themselves as a Klingon vessel. (Star Trek VI: The Undiscovered Country)
In an ironic production mistake, the book's title should have been correctly spelled as "
Introduction to Klingon Gramma
The book was a modified version of the 1951 catalog for Alloy Steel Products, Inc.