Reddit mentions of The Assassin Legends: Myths of the Isma'ilis

Start with Farhad Daftary's The Assassin Legends: Myths of the Isma'ilis (I. B. Tauris, 1995) if you want a solid introduction. Another really excellent book on them is Marshall Hodgson's book The Secret Order of Assassins: The Struggle of the Early Nizari Ismai'lis Against the Islamic World (University of Pennsylvania Press, 2005).

Lewis' work is out of date, but Hodgson's is still quite relevant. I am pasting below the entry from Encyclopedia of Islam, 2nd Ed., which was written by Lewis. It has some good introductory information and does have a few relevant bibliographic items listed. I would just post the link, but it is behind a proxy.

> Ḥas̲h̲īs̲h̲iyya, a name given in mediaeval times to the followers in Syria of the Nizārī branch of the Ismāʿīlī sect. The name was carried from Syria to Europe by the Crusaders, and occurs in a variety of forms in the Western literature of the Crusades, as well as in Greek and Hebrew texts. In the form 'assassin' it eventually found its way into French and English usage, with corresponding forms in Italian, Spanish and other languages. At first the word seems to have been used in the sense of devotee or zealot, thus corresponding to fidāʾī [q.v.]. As early as the 12th century Provençal poets compare themselves to Assassins in their self-sacrificing devotion to their ladies (F. M. Chambers, The troubadours and the Assassins, in Modern Language Notes, lxiv (1949), 245 ff.; D. Scheludko, Über die arabischen Lehnwörter im Altprovenzalischen, in Zeitschrift für romanische Philologie, xlvii (1927), 423). But soon it was the murderous tactics of the Nizārīs, rather than their selfless devotion, that fascinated European visitors to the East, and gave the word a new meaning. From being the name of a mysterious sect in Syria, assassin becomes a common noun meaning murderer. It is already used by Dante ('lo perfido assassin ...', Inferno, xix, 49-50), and is explained by his commentator Francesco da Buti, in the second half of the 14th century, as 'one who kills another for money'.
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> During the 17th and 18th centuries the name assassin—and the sect that first bore it—received a good deal of attention from European scholars, who produced a number of theories, mostly fantastic, to explain its origin and significance. The mystery was finally solved by Silvestre de Sacy in his Mémoire sur la dynastie des Assassins et sur l'origine de leur nom, read to the Institut in 1809 and published in the Mémoires de l'Institut Royal, iv (1818), 1-85 (= Mémoires d'histoire et de littérature orientales, Paris 1818, 322-403). Using Arabic manuscript sources, notably the chronicle of AbūS̲h̲āma, he examines and rejects previous explanations, and shows that the word assassin is connected with the Arabicḥas̲h̲īs̲h̲ [q.v.]. He suggests that the variant forms Assassini, Assissini, Heyssisini etc. in the Crusading sources come from alternative Arabic forms ḥas̲h̲īs̲h̲ī (pl. ḥas̲h̲īs̲h̲iyya or has̲h̲īs̲h̲iyyīn) and ḥas̲h̲s̲h̲ās̲h̲ (pl. ḥas̲h̲s̲h̲ās̲h̲īn). In confirmation of this he was able to produce several Arabic texts in which the sectaries are called ḥas̲h̲īs̲h̲ī, but none in which they are called ḥas̲h̲s̲h̲ās̲h̲. Since then, the form ḥas̲h̲īs̲h̲ī has been amply confirmed by new texts that have come to light—but there is still, as far as is known, no text in which the sectaries are called ḥas̲h̲s̲h̲ās̲h̲. It would therefore seem that this part of S. de Sacy's explanation must be abandoned, and all the European variants derived from the Arabicḥas̲h̲īs̲h̲ī.
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> This revision raises again the question of the meaning of the term. Ḥas̲h̲īs̲h̲ is of course the Arabic name of Indian hemp—cannabis sativa—and ḥas̲h̲s̲h̲ās̲h̲ is the common word for a hashish-taker. De Sacy, while not accepting the opinion held by many later writers that the assassins were so called because they were addicts, nevertheless explains the name as due to the secret use of hashish by the leaders of the sect, to give their emissaries a foretaste of the delights of paradise that awaited them on the completion of their missions. He links this interpretation with the story told by Marco Polo, and found also in other eastern and western sources, of the secret 'gardens of paradise' into which the drugged devotees were introduced (Marco Polo, edd. A. C. Moule and P. Pelliot, London 1938, i, 40 ff.; cf. Arnold of Lübeck, Chronicon Slavorum, iv, 16; J. von Hammer, Sur le paradis du Vieux de la Montagne, in Fundgruben des Orients, iii (1813), 201-6—citing an Arabic romance, in which the drug used is called Band̲j̲). This story is early; the oldest version of it, that of Arnold of Lübeck, must date from the end of the 12th century. Their chief, he says, himself gives them daggers which are, so to speak, consecrated to this task, and then “et tunc poculo eos quodam, quo in extasim vel amentiam rapiantur, inebriat, et eis magicis suis quedam sompnia in fantastica, gaudiis et deliciis, immo nugis plena, ostendit, et hec eternaliter pro tali opere eos habere contendit” (Monumenta Germaniae historica, xxi, Hanover 1869, 179). This story, which may well be the earliest account of hashish dreams, is repeated with variants by later writers. It is, however, almost certainly a popular tale, perhaps even a result rather than a cause of the name ḥas̲h̲īs̲h̲iyya. The use and effects of hashish were known at the time, and were no secret; the use of the drug by the sectaries, with or without secret gardens, is attested neither by Ismāʿīlī nor by serious Sunnī authors. Even the name ḥas̲h̲īs̲h̲iyya is local to Syria (cf. Houtsma, Recueil, i, 195; Ibn Muyassar, Annales, 68) and probably abusive. It was never used by contemporaries of the Persian or any other non-Syrian Ismāʿīlīs; even in Syria it was not used by the Ismāʿīlīs; themselves (except in a polemic tract issued by the FāṭimidCaliph al-Āmir against his Nizārī opponents—A. A. A. Fyzee, al-Hidāyatu 'l-āmirīya, London-Bombay 1938, 27), and only occasionally even by non-Ismāʿīlī writers. Thus Maḳrīzī, in a fairly lengthy discussion of the origins and use of hashish, mentions a Persian mulḥid (probably an Ismāʿīlī) who came to Cairo at about the end of the 8th century A.H. and prepared and sold his own mixture of hashish—but does not call the Ismāʿīlīs ḥas̲h̲īs̲h̲iyya, or mention any special connexion between the sect and the drug (Ḵh̲iṭaṭ, Būlāḳ, ii, 126-9). Ḥas̲h̲īs̲h̲ī would thus appear to have been a local Syrian epithet for the Ismāʿīlīs, probably a term of contempt—a criticism of their behaviour rather than a description of their practices.
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> (B. Lewis)
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> Bibliography
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> B. Lewis, The sources for the history of the Syrian assassins, in Speculum, xxvii (1952), 475-89
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> idem, The Ismāʿīlites and the Assassins, in A history of the Crusades, editor-in-chief K. M. Setton, i, The first hundred years, ed. M. W. Baldwin, Philadelphia 1955, 99-132
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> M. G. S. Hodgson, The Order of Assassins, The Hague 1955, espec. 133-7. For the history of the sect see ismāʿīliyya and nizārīs.
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> [The entry 'Ḥas̲h̲īs̲h̲iyya' was originally published in print in 1966 (fascicule 43-46, pp. 267-268).]
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>[Print Version: Volume III, page 267, column 2]
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> Citation:
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> Lewis, B. "Ḥas̲h̲īs̲h̲iyya." Encyclopaedia of Islam, Second Edition. Edited by: P. Bearman; , Th. Bianquis; , C.E. Bosworth; , E. van Donzel; and W.P. Heinrichs. Brill, 2011. Brill Online.