Using a Learned Treatise at Trial

John P. Gismondi
May 1999

You’re in a hotly contested trial and the verdict is most likely to hinge on whose expert the jury believes. It’s the night before you’re scheduled to cross-examine the opponent’s “hired gun” and you have some great quotes from a textbook that you would like to use for impeachment in tomorrow’s showdown. Two questions come to mind as you feverishly make your final preparations: What sort of foundation do I have to lay in order to confront the witness with the learned treatise? If I lay the proper foundation, how extensively can the book be used, i.e. as evidence of the truth of the matters stated therein, or only for impeachment purposes?

Alternatively, consider this possible, though less likely, scenario. You are preparing for tomorrow’s direct examination of your own expert witness. While the expert appears to be a fine, well-informed individual, you’re beginning to have second thoughts about whether or not his opinion will “sell” to the jury. At the last minute, you discover a great passage in a learned treatise which squarely supports the opinion your expert has been espousing since day one. This question immediately leaps to mind: Can I have the expert read from the textbook during direct examination? In federal court, the controlling law is contained in Federal Rule of Evidence 803(18). In Pennsylvania, the common law continues to control, for our new Evidence Code does not contain a specific provision on the learned treatise issue.

Laying the Proper Foundation

Before determining how extensively the learned treatise can be used either on direct or cross, we must first be assured that the text can be used at all, i.e. that its properly authenticated. In federal court, Rule 803(18) indicates that a learned treatise is authoritative if it is “established as a reliable authority by the testimony or admission of the witness or by other expert testimony or by judicial notice.” The first thing to note about the rule is that it only requires the book be recognized as a “reliable authority,” it is not necessary to prove that the book is the authority on a certain subject.

Who may authenticate a learned treatise? According to the rule, it can be not only the witness presently on the stand, but any other competent expert who can legitimize the text. Thus, while the most common situation is to have the treatise recognized by the witness with whom it is going to be discussed, counsel could authenticate a learned treatise through witness No. 1 and then seek to use the book during the testimony of witness No. 2. In fact, it is probably not even necessary in this latter circumstance that witnesses 1 and 2 be on “the same side” in the litigation. In other words, the plaintiff could presumably authenticate a treatise through his or her own expert and then use it when cross-examining a defense expert.

Pennsylvania law is generally in accord with the federal rule in holding that a learned treatise may be used so long as some competent expert has verified that the text is recognized as authoritative by those in a particular field. See, for example, McDaniel v. Merck, Sharp & Dohme, 533 A.2d 436 (Super. 1987), in which the Superior Court held that the trial court should have permitted the plaintiff to cross-examine a defense expert with a learned treatise that had been authenticated by his (the plaintiff’s) expert even though the defense expert was unfamiliar with the work. As the court noted, “as long as [the plaintiff] has produced her own expert to verify that the particular publications are authoritative in the field, an expert [defense] witness may be tested by reference to those publications.”

Thus, the first step in using a learned treatise is to have some expert-usually your own but potentially one from the other side-testify that the book is accepted as authoritative. An occasional stumbling block in laying the foundation concerns the question of what exactly the expert must recognize as authoritative: the textbook in general or the particular passage which will eventually be utilized. While there is no Pennsylvania or federal case specifically addressing this point, it seems safe to assume the law would permit the textbook to be used even though a witness is not familiar with a particular passage.

Using the Text on Cross-Examination

Once authenticated, the most likely use of a learned treatise is to cross-examine the opposing expert. What exactly can you do with the text in that regard? Certainly if on direct examination the opposing expert testified to opinion “X,” you can confront him with an authenticated text and ask him, “Mr. Expert, doesn’t this treatise say ‘Y’ is true?” That exchange, of course, represents the classic impeachment use of a learned treatise. A less obvious issue is whether the passage, once having been read to the expert, comes in merely for impeachment purposes or as substantive evidence as well.

Federal Rule 803 (18) is specifically termed an exception to the hearsay rule and thus, any excerpt from an authenticated treatise is, by definition, admissible for the truth of the matter asserted, not merely as impeachment evidence. Pennsylvania law, however, differs with this position. In Majdic v.Cincinnati Machine Company, 537 A.2d 334 (Super. 1988), the Superior Court stated that an expert witness may be cross-examined regarding a publication which the expert notes as a standard in the field. However, attorneys may use the text only to challenge the credibility of the witnesses’ opinions. Such texts are hearsay and may not be admitted into evidence for jury consideration. Thus, in federal court a learned treatise may be used either to impeach the opposing expert or as substantive evidence, whereas in state court it may be used only for impeachment purposes.

Using the Text on Direct Examination

Using a learned treatise on direct examination represents undoubtedly the least common, and least understood, scenario. As noted at the outset, this circumstance would arise if counsel attempted to bolster his own expert by having him read from a text that endorses his earlier-stated opinion.

Federal rule 803(18) indicates that a learned treatise can be used by an expert witness “to the extent – relied upon by [him] in direct examination.” The key, of course, is what is meant by “relied upon.” The potential danger of widespread use of learned treatises on direct examination is a mad scramble by both sides to inundate the jury with textbook quotes favorable to their position, none of which are subject to cross examination. Thus, a party attempting to prevent such use of a learned treatise can credibly argue that the opposing expert arrived at his opinion based on his own personal experience and education, not his reading of the text. Thus, he was not truly “relying on” the treatise in formulating his opinion.

Contrary to the federal rule, Pennsylvania law, as stated in Majdic, supra., prohibits the use of a learned treatise on direct examination.


Before the treatise can be used for any purpose, the book must be authenticated, i.e., an expert must testify that the text is generally regarded as authoritative or reliable by those in a particular field.

The expert who authenticates the text may be either the one presently on the stand or some other expert who has testified earlier in the case.

In order to authenticate the treatise, it is not necessary that the expert have read the particular passage at issue (or even the text at all).

On cross-examination, a properly authenticated treatise may be used both for substantive and impeachment purposes in federal court whereas in state court it can be used only for impeachment purposes.

On direct examination, a properly authenticated treatise may be introduced in federal court to the extent the expert has relied upon it whereas in state court, the learned treatise remains hearsay and, therefore, cannot be introduced on direct ex