Karen Hicks (plaintiff) received a polio vaccine in 1962, when she was about five years old. The vaccine was administered as part of a popular, respected public health campaign. About 39 years later, Hicks was diagnosed with two malignant brain tumors. Hicks brought a products liability suit against Charles Pfizer & Co. (Pfizer) (defendant), alleging that the vaccine caused her tumors and that Pfizer manufactured the vaccine. At trial, Hicks sought to introduce four 1962 newspaper articles from different authors and different newspapers, each of which linked Pfizer to the vaccine Hicks received. Hicks was unable to produce any other evidence linking Pfizer to the vaccine. Pfizer objected to the introduction of the articles on hearsay grounds and moved for summary judgment.