Of great importance for all historical study are the sources used in forming narrative perspectives. Some historians are relatively inclusive in their acceptance of source material, drawing from a wide variety of disciplines and quality of material. Others are more selective in the criterion employed to discern source materials for their historical reconstructions. Crossan falls into the later camp, as he employs relatively few sources in his construction of the historical Jesus. Crossan believes that the fourfold narrative of the canonical gospels presents a problem for modern Christianity, and that the historical truth behind the canonical Jesus must be discovered using only the earliest materials. For his construction, Crossan employs three forms of material. First, he engages in use of cross-cultural anthropology to provide a general understanding of the first century Jewish-Mediterranean context. Second, he considers the accounts of the Greco-Roman and Jewish historians of the age, chiefly Tacitus and Josephus. These accounts Crossan treats with a certain level of scrutiny on most points,  though some have argued that his critique on non-Christian historical sources only seems to appear in Crossan’s work when his construction cannot make sense of the status quo within the traditional historical record.
Finally, Crossan considers the literary perspectives on Jesus as offered in gospel accounts. The canonical gospel narratives are for Crossan relatively late conglomerate layers of deliberately theological material, and thus cannot be fully trusted to provide a totally accurate perspective on Jesus of Nazareth. Seeking to employ materials from as early as possible, Crossan tends to rely on sources such as the Gospel according to Mark, Q (as found in the Matthean and Lucan accounts), and the Gospel of Thomas. These sources Crossan then subjects to a reading focused on criterion such as multiple attestation, contextual originality or dissimilarity, and overall coherence of message. The resulting passages, parables, sayings, and other material form the basis for Crossan’s reconstruction of the historical Jesus. All told, using the context of cultural anthropology, coordinating historical accounts of period scholars, and a historical-critical approach to gospels material, Crossan arrives at the sources he believes are historically sound enough to provide for his reconstruction of the historical Jesus.
On the other hand, N. T. Wright approaches source material in a manner that draws upon a wide range of sources, without becoming overly skeptical of materials, creating a personalized reconstruction of Jesus, or unquestioningly accepting the traditional perspective of Jesus of Nazareth. Whereas Crossan attempts to perform certain tests on materials before considering their historical merit, Wright contextualizes the array of available historical sources before employing them for his historical construction. Wright, perhaps because of his work in Biblical Studies and his works on the development of Christian doctrine, has a higher view of the historicity of New Testament text than Crossan, and cites widely from a variety of Biblical sources. Wright takes a less qualified view of sources than Crossan, though by no means does he unquestioningly accept as truth the accounts recorded within the plethora of sources that he employs. Wright places emphasis on non-canonical sources such as Qumran documents, Josephus, Philo, Rabbinic works, and Gnostic texts, though contextualization forms perhaps the greatest historiographical factor for judging the quality a source. If the work in question builds into the narrative presented by other sources, Wright argues that such a position has the best historical footing. Summing Wright’s position on sources, he argues that consensus building sources form the best critical foundation for research, be they canonical, Greco-Roman, Jewish, or otherwise.
 John Dominic Crossan. Jesus: A Revolutionary Biography. San Francisco: Harper San Francisco, 1994. X.
 Ibid., xii.
 Ibid., xii.
 Crossan offers corrections of material concerned with Jesus, John the Baptist, and Pontius Pilate, arguing that later scribes and/or the historian himself (primarily Josephus in these instances) must be read with skepticism (see pages 160-163 in Jesus: A Revolutionary Biography).
 Ibid., xiii.
 Crossan’s applied use of the Gospel of Thomas, both as an independence source for historical Jesus material as well as his early dating of the document, has at least been called into question by scholars such as Charles Quarles (“The Use of the Gospel of Thomas in the Research on the Historical Jesus of John Dominic Crossan”, Catholic Biblical Quarterly July 1, 2007) and Nicholas Perrin (“Thomas: The Fifth Gospel”, Journal of the Evangelical Theological Society March 1, 2006).
 As indicated in the opening section of The Historical Jesus: The Life of a Mediterranean Jewish Peasant, the final source material that Crossan finds historically accurate seems paltry compared to the canonical accounts, as he can list nearly all of the sayings of the historical Jesus on a few pages of his book (see pages xiii to xxvi).
 Tom Wright. Simply Jesus. New York: Harper Collins, 2011. ix-x.
 Ibid., 8-9.
 Though Wright by no means reads the canonical gospels as pure, post-enlightenment western-style history, instead understanding them more as first century Mediterranean theological literature that conveys historical fact.
 Ibid., 235-237. This view is similarly reinforced in The New Testament and the People of God.
 N.T. Wright. Jesus and the Victory of God. Minneapolis: Fortress Press, 1996. Indexed, 713-717; 727-729.
 Ibid., 83-124.
 Wright’s historiography falls more in line with a more traditional approach to the historical-critical methodology, and does not convey many of the revisionist qualities of Crossan’s work.