Which of the following primary sources would best help someone examine how the printing press and printed books influenced Europe?

The best primary source to examine how the printing press and printed books influenced Europe would be a historical document that discusses or reflects the impact of these innovations during the time they were introduced and widely adopted. Based on this criterion, the most suitable primary source would be "Gutenberg's Bible" or any original edition of a printed book from the early years of the printing press.

The Gutenberg Bible, printed by Johannes Gutenberg in the mid-15th century, is hailed as the first major book printed using movable type in the Western world. It revolutionized printing techniques and had a profound impact on Europe. By examining an original copy of the Gutenberg Bible or other early printed books, researchers can analyze the technological advancements, the dissemination of knowledge, and the cultural, social, and religious transformations that resulted from the availability of printed materials.

Additionally, other valuable primary sources to examine this influence might include contemporary accounts such as diaries, letters, or pamphlets that discuss the printing press, its advantages, perceptions, and effects on society and knowledge. These sources would provide firsthand insights into the specific ways in which the printing press and printed books influenced Europe during their initial introduction and subsequent proliferation.