I am frequently asked by more advanced collectors about the standard works they should obtain to further their understanding of their chosen specialty. Building a good numismatic reference library is of prime importance in gaining the maximum enjoyment from your hobby and it is always advantageous to be well informed when entering the coin market as a buyer. Books - especially rare out of print standard works - can also be an excellent investment (frequently better than the coins themselves). The following recommendations are specialized works of reference which definitely require a fuller comprehension of the subject matter. Also review general works, intended as introductions to the subject. The number of reference works and specialized studies in the Greek series is truly daunting, and as many of them have been out of print for years and are, in consequence, extremely hard to find (other than in a good institutional library) I shall confine my comments to important sources of reference material which are more readily available - either because they have appeared in recent years or are older works which have been reprinted. Of particular value are the catalogues of large collections, both public and private. Some of these are in the large format "Sylloge Numorum Graecorum" series, such as SNG Copenhagen, in which the vast collection of The Danish National Museum is published; SNG ANS, which contains part of the magnificent Greek holdings of the American Numismatic Society in New York; and SNG von Aulock, the publication of the collection of coins of Asia Minor assembled by Hans von Aulock, including many pieces of the Roman period (i.e. 'Greek Imperial'). The 29 volumes of the British Museum Catalogue of Greek Coins ("BMC Greek") appeared in the closing decades of the 19th century and the opening decades of the 20th. Although they have been reprinted and can be acquired individually, the scholarship is, of course, largely outdated, though they remain a highly important source of reference because of the sheer size of the collection. On a more manageable scale, and generally less expensive, are the publications of smaller collections, such as The Boston Museum of Fine Arts, The Arthur Dewing Collection, The Gulbenkian Collection, The Hunterian Collection (University of Glasgow), The Jameson Collection, The Ludwig Collection (Basel), The McClean Collection (Fitzwilliam Museum, Cambridge), The Pozzi Collection (auction catalogue), and The Weber Collection. Keen collectors of the Greek series should try to acquire at least some of these, as they contain a wealth of material, generally presented with excellent cataloguing expertise. Those with more specific interests will often find works devoted to the series of their choice, for example Oscar Ravel's "Descriptive Catalogue of the Collection of Tarentine Coins formed by M.P. Vlasto", Kenneth Jenkins' "The Coinage of Gela", Erich Boehringer's "Die Münzen von Syrakus", Ravel's "Les Poulains de Corinthe", and J.N. Svoronos' "Trésor des monnaies d'Athenes", reprinted in the 70's as "Corpus of the Ancient Coins of Athens". This is just a small selection of the specialized works on the coinages of individual Greek states. If you need further advice, just contact me via e-mail. The coinages of some of the Greek kingdoms have also received exhaustive scholarly treatment, though large gaps remain (e.g. the highly important coinage in the name of Lysimachus of Thrace). The lifetime and posthumous issues bearing the name of Alexander of Macedon, for long lacking a truly authoritative work, eventually found it in 1991 with the publication of Martin Price's epic "The Coinage in the Name of Alexander the Great and Arrhidaeus". The Seleucid Kingdom has probably received the most attention, though Edward Newell's "The Coinage of the Eastern Seleucid Mints" and "The Coinage of the Western Seleucid Mints" currently remain the standard works of reference. The Ptolemaic Kingdom of Egypt is covered in Svoronos' 1904 classic "Ta nomismata tou kratous ton Ptolemaion". However, it was written in modern Greek, has never been reprinted, and is prohibitively costly when available. We are all awaiting a revised version in English, which apparently is on the way. The Roman coinage is a more orderly series and in consequence the number of standard works of reference is far fewer than in the case of Greek. The Republican coinage has received much attention, the principal bone of contention amongst scholars centering around the question of precise chronology. The standard work since its publication in 1974 has been Michael Crawford's masterly "Roman Republican Coinage". Prior to this, the principal references had been the Rev. Edward Sydenham's "The Coinage of the Roman Republic" (1952) and the three-volume British Museum Catalogue of Coins of the Roman Republic ("BMCRR") written by Herbert Grueber and published in 1910. Both of these works are still useful, especially BMCRR which contains a prodigious amount of historical data. The most recent treatment of the ponderous cast bronze coinage of Rome and other central Italian states will be found in "Italian Cast Coinage" by Bradbury Thurlow and Italo Vecchi (1979). The entire coinage of the Roman Empire is now covered in the epic ten-volume set of "The Roman Imperial Coinage", commonly referred to as "RIC". This prodigious undertaking was begun by Mattingly and Sydenham in 1923 and was only completed in 1944 with the publication of Kent's Volume X. However, it is still an ongoing process, as a number of the earlier volumes are in serious need of revision, and Volume I was already rewritten by Sutherland as long ago as 1984. After "RIC" the next most important reference work is the six-volume British Museum Catalogue of Coins of the Roman Empire ("BMCRE"). However, this work, which began in the same year as RIC (1923), has so far progressed only as far as AD 238 (Balbinus and Pupienus) and, disappointingly, nothing has been published since Robert Carson's Volume VI in 1962. These catalogues contain considerably more introductory material than the RIC volumes covering the same period and are more fully illustrated, so they remain of considerable importance. Another important series which is actively progressing is the Bibliotheque Nationale's "Catalogue des Monnaies de l'Empire Romain". Four volumes have so far been published, three of them authored by Jean-Baptiste Giard and covering the period Augustus to Nerva (29 BC - AD 98), the other by Sylviane Estiot dealing with the regions of Aurelian, Tacitus and Florian (AD 270-276). As (and if) it continues to progress this series will grow in importance, as the French National Collection is one of the most comprehensive in the world. A series which has already been completed, thanks to the untiring efforts of the late Anne Robertson, is the five-volume set of "Roman Imperial Coins in the Hunter Coin Cabinet" (University of Glasgow). Completed over a twenty-year period (1962-82) the extensive introductory material in each volume makes this work especially important for the coinage of the second half of the 3rd century, where RIC is weak and BMCRE has not even reached. Surprisingly, the late 19th century standard work on the series, Henry Cohen's "Description Historique des Monnaies frappées sous l'Empire Romain" (referred to simply as "Cohen") is still widely used, especially in Europe. Its remarkable longevity may be attributed to the simplicity of the arrangement of the listings (alphabetically by reverse legend) which aids quick identification - a boon to dealers who may be short of time. In addition to the above, there are numerous more specialized works of reference relating to the Roman Imperial series, such as Sutherland's "The Cistophori of Augustus", David MacDowall's "The Western Coinages of Nero", Colin Kraay's "The Aes Coinage of Galba", Ian Carradice's "Coinage and Finances in the Reign of Domitian", William Metcalf's "The Cistophori of Hadrian", Philip Hill's "The Dating and Arrangement of the Undated Coins of Rome, A.D. 98-148", the same author's "The Coinage of Septimius Severus and his Family of the Mint of Rome, A.D. 193-217", Pierre Bastien's "Le Monnayage de Bronze de Postume", and Carson, Hill and Kent's "Late Roman Bronze Coinage, A.D. 324-498". The previously much-neglected 5th century coinage has, over the past decade, received much attention, principally by Wolfgang Hahn in "Moneta Imperii Romani-Byzantini, die Ostpragung des Romischen Reiches im 5. Jahrhundert (408-491)" and by Philip Grierson and Melinda Mays in the Dumbarton Oaks "Catalogue of Late Roman Coins from Arcadius and Honorius to the Accession of Anastasius". However, both of these have, to some extent, been superseded by the new RIC Volume X. A new series being produced in Vienna, "Moneta Imperii Romani", is also of considerable interest, being published in numerous parts, each being a detailed study of a particular reign or period. Parts already available are "Tiberius and Caligula", "Marcus Aurelius to Commodus", "Maximinus I Thrax", and "Aurelian". The local coinages of the Roman Empire produced by numerous provincial mints, principally in the eastern provinces, have, in the past, seldom received individual attention. These coinages have traditionally been treated as the final phase of the Greek coinage (hence 'Greek Imperial') and have appeared in catalogues of Greek coins where the primary arrangement is geographical. Hence, the chronological significance of the series had been largely obscured until the appearance in 1992 of the first volume of "Roman Provincial Coinage". Authored by Andrew Burnett, Michel Amandry, and Pere Pau Ripolles, this brilliant new work deals with the local coinages of the period 44 BC to AD 69, from the death of Caesar to the death of Vitellius. Other volumes are in preparation and Volume II, covers the Flavian emperors. This is one of the most important new series to be launched in many years and, despite the not inconsequential price of the initial volume (around $325), is highly recommended. The coinage of Roman Egypt has been extensively covered by a number of excellent publications, including J.G. Milne's "Catalogue of Alexandrian Coins, University of Oxford, Ashmolean Museum"; "Katalog Alexandrinischer Kaisermünzen der Sammlung des Instituts für Altertumkkunde der Universitat zu Koln", by Angelo Geissen and Wolfram Weiser; G. Dattari's classic work "Monete Imperiali Greche Numi Augg. Alexandrini", published in Cairo in 1901; and, of course, the volume of BMC Greek devoted to "Alexandria and the Nomes". Important for Roman Syria are Waldemar Wruck's "Die Syrische Provinzialpragung von Augustus bis Traian" and Alfred Bellinger's "The Syrian Tetradrachms of Caracalla and Macrinus"; and still useful for Roman Cappadocia is Sydenham's "The Coinage of Caesarea in Cappadocia". Unlike the earlier decades of the 20th century, the past thirty-five years have seen enormous activity in the field of Byzantine numismatics and the appearance of many new works of reference. Prior to this, the only catalogues available were J. Sabatier's "Description générale des Monnaies Byzantines" (1862); Warwick Wroth's British Museum Catalogue of Imperial Byzantine Coins ("Wroth"), published in 1908; Ivan Tolstoi's "Monnaies Byzantines" (1912-14, with Russian text); and the "Ratto" auction catalogue of 1930, containing 2,701 lots of Byzantine and other coins of related series. Virtually nothing appeared after this until 1966, when the first volume of the epic "Catalogue of the Byzantine Coins in the Dumbarton Oaks and Whittemore Collections" ("DO" or "DOC") was published. This series, authored by Philip Grierson, Alfred Bellinger, and Michael Hendy, is now complete (down to 1453) in five volumes, the final two having been published in 1999. This is unquestionably the most authoritative work of reference on this remarkable series and the introductory text contains brilliant analyses of the different issues. Also of great importance for Byzantinists is the three-volume set "Moneta Imperii Byzantini" ("MIB") by Wolfgang Hahn, published between 1973 and 1981. The main drawbacks are that it covers only the period Anastasius I to the sole reign of Leo III (AD 491-720) and the text is in German. Of somewhat lesser importance is the two-volume "Catalogue des Monnaies Byzantines de la Bibliotheque Nationale" ("BN") by Cécile Morrisson, published in Paris in 1970. Two useful reference works by Harlan Berk are "Roman Gold Coins of the Medieval World, 383-1453 A.D." (1986) and "Eastern Roman Successors of the Sestertius" (1988), both providing helpful price guides. There are also a number of more specialized works, such as "Studies in Early Byzantine Gold Coinage", edited by Wolfgang Hahn and William Metcalf; "L'Hexagramme" by Panayotis Yannopoulos; and Simon Bendall's "A Private Collection of Palaeologan Coins". Michael Hendy's important "Coinage and Money in the Byzantine Empire, 1081-1261" (1969) has now been largely superseded by the same author's Volume IV of the Dumbarton Oaks Catalogue.