Njáls saga stands out among the Sagas of Icelanders (Íslendingasögur) in that an unusually high number of early manuscript witnesses are preserved. The saga is extant in around 60 manuscripts, 21 of which are parchment manuscripts from the period 1300-1600.
Despite the high number of parchment manuscripts, no single medieval witness preserves a complete text. All of these older manuscripts are fragmentary. Some of them amount to only a couple of leaves; six, however, may be said to contain the bulk of the saga:
- Reykjabók (AM 468 4to), c. 1300-1325
- Gráskinna (GKS 2870), c. 1300 and with additions from c. 1500-1550
- Möðruvallabók (AM 132 fol.), c. 1330-1370
- Kálfalækjarbók (AM 133 fol.), c. 1350
- Skafinskinna (GKS 2868 4to), c. 1350-1400
- Oddabók (AM 466 4to), c. 1460
The saga is generally believed to have been compiled around 1280 and there are 12 witnesses that date to the 14th century, i.e. 5 of the manuscripts listed above and 7 from the collection of fragments catalogued as AM 162 b fol.
These fragments are:
- AM 162 b fol. β (beta), c. 1300
- AM 162 b fol. δ (delta), c. 1300
- AM 162 b fol. ζ (zeta), c. 1325
- AM 162 b fol. κ (kappa), c. 1350
- AM 162 b fol. γ (gamma), c. 1325
- AM 162 b fol. θ (theta), c. 1325
- AM 162 b fol. η (þeta), c. 1350

AM 162 b fol. δ
In the 17th century, there was one additional parchment codex still extant which was subsequently lost. This was called Gullskinna by Bishop Brynjólfur Sveinsson, and a number of 17th- and 18th-century paper copies of it are still extant.
The most significant research into the manuscripts of Njáls saga has, in the past, been undertaken in conjunction with the preparation of printed editions of the saga. The principal editions of the saga are listed below:
Editio princeps, ed. Ólafur Olavius (Copenhagen, 1772). Text follows Reykjabók with variant readings from Möðruvallabók and Kálfalækjarbók in the apparatus.
- Konráð Gíslason and Eiríkur Jónsson, 2 vols (Det kongelige nordiske Oldskrift-Selskab: Copenhagen, 1875-89). Text based on Reykjabók with variants in main text/apparatus from all other medieval mss and some post-medieval paper mss.
- Finnur Jónsson (Altnordische Saga-Bibliothek: Halle, 1908). Text based on Reykjabók but variants introduced into main text from other medieval mss.
- Einar Ólafur Sveinsson (Hið Íslenzka fornritafélag: Reykjavík, 1954). Text based on Möðruvallabók with variants from other medieval mss.
These editions were conceived and executed within the genealogical theoretical framework of 19th-century textual criticism. Einar Ólafur’s Íslenzk fornrit edition was also strongly influenced by the so-called ‘Icelandic School’ of saga studies whose proponents viewed the sagas as the products of individual authors. These editions have, in turn, influenced the ways in which scholars and general readers have read and interpreted Njáls saga, who have had to work with editions that mix texts of different manuscripts. One exception is Sveinn Yngvi Egilsson’s recent edition of the Reykjabók text of Njáls saga (Brennu-Njáls saga. Texti Reykjabókar. Reykjavík: Bjartur, 2003).
Within the last decades however, views on textual criticism and manuscript studies have been transformed, partly due to new currents associated with the so-called ‘New Philology’, and partly on account of technical developments and the possibilities that electronic representation and editing have opened up. Textual criticism has turned away from the genealogical or ‘best-text’ approaches advocated by Karl Lachmann and Joseph Bédier in the 19th and early 20th centuries; rather than seeking to fix the text or freeze it in its most ‘original’ form, scholars are increasingly exploring the textual variation that is found in the manuscript transmission of any one saga. The fact that no two manuscripts of a given saga are identical invites us to investigate the nature of their difference but moreover, to ask why they are different — whether they served different purposes, grew out of a different environment, were meant for a different audience. This project will produce answers to these questions with reference to Njáls saga.