Introduction to Klingon Grammer

From Memory Alpha, the free Star Trek reference

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 Grammar."

The book was a modified version of the 1951 catalog for Alloy Steel Products, Inc.