The Mongol states of both Persia and China have received extensive coverage since the time of their conception, no less from mediaeval scholars than from academics from various fields today. Primary sources from these two great regions are rich and detailed and to this day are still providing researchers with ample material for investigation. Michal Biran has bravely chosen an area for her vigorous research which lay between these two great power blocs and selected a figure who up until now has often been ignored or underestimated. Her welcome study of Qaidu Khan and the formative years of his Central Asian Khanate succeeds in establishing Qaidu as one of the major players in the reconfiguration of the Mongol Empire in the 13th century. One reason for this oversight which has led to Qaidu's marginalisation has been the lack of source materials written from within his own region. In contrast to the detailed chronicles composed in the courts of the neighbouring khanates, only one work is known to have been written from within Qaidu's territory, the 14th century Mulháaqat al-s®urahá of Jamal Qarshi. Most of the detail of Qaidu's life must be gleaned from the sources written in the neighbouring Toluid states, Mamluk Egypt, the Caucasus or from travelogues compiled by European travellers. Unfortunately most of these sources especially the Persian and Chinese material are partisan and betray their hostility toward the ambitious prince, viewing Qaidu as a rebel and an enemy. Where the writers have a more objective view as is the case with the Armenian and Mamluk chroniclers their details are sketchy and their reports imply that Qaidu's territory and political manoeuvring are distant from their concerns. Even travellers like Marco Polo who included a chapter on 'King Caidu' in his narratives were more concerned with grander matters to the east or south and did not grant the Ögödeid aspirant his full dues. Faced with these formidable obstacles Michal Biran has performed an admirable and meticulously accomplished task. Armed with an enviable knowledge of languages including Persian, Arabic and Chinese she has been able to retrieve an impressive amount of data from a wide range of sources and to present a convincing and radically new portrait of this remarkable mediaeval Mongol potentate. In her book Biran correlates the various sources and succeeds in building not only a rounded picture of Qaidu, his deeds and motivation but presents a picture of the internal administration of his state in its formative stages and the relationship of this state with the rest of the Mongol world. She is able to show that Qaidu's driving motivation was not as some would have it, to acquire the mantle of the Qa'an, nor to promote the return to the traditional values of the nomadic lifestyle and culture of the steppes in contrast to the 'progressive' sedentary regimes of the Il-Khans or the Yuan. Qaidu's motivation for seeking power, Biran convincingly argues, was to redress the wrongs done to his own branch of the royal family, the Ögödeids. He sought to establish a state representing the house of Ögödei which was at least equal in status to and commensurate with the other Mongol states. Such was his stature and political dexterity backed by military aptitude that he was able to achieve to some degree these aims in his own lifetime. However, lacking their father's prestige and genius his sons were unable to sustain these considerable achievements and within ten years of his death in 1301 they had lost much of their political power and the Mongol state over which they ruled became known to history as the Chaghadaid Khanate. Michal Biran traces Qaidu's rise from his birth in 1235 in Ögödei's ordu, through his first territorial base in Qayaliq and then details the intrigues and manoeuvring following the Qa'an Möngke's death in 1259. She shows how Qaidu was able to manipulate other such Mongol princes as Baraq to serve his own ends and that he was not averse to switching allegiances when it might suit his own purposes. Qaidu's confrontation with the Qa'an, Qubilai, which became not only a political conflict between the house of Tolui and the house of Ögödei but also one of personal enmity between the two men, is analysed in depth and the varied effects that the antagonism with the Il-Khans of Persia had on trade links and political exchanges between China and Iran are clarified. The decisive role of the Jochids in Qaidu's rise even though eventually this was to result in the cessation of Jochid control over Transoxiana is highlighted and the commercial contacts with the Mamluks of Egypt are recognised. After carefully collecting, analysing and interpreting all the diverse sources, Michal Biran is also able to plot the shift of Qaidu's kingdom into a state dominated by the Chaghadaids and the collapse of his Ögödeid regime after his death. The nature of his state and its internal administration is not overlooked and ample space is found for careful consideration of the role of the army, religion and the economy in the formation and development of the Ögödeid polity. Lacunae remain but they are unambiguously acknowledged and their individual significance is reduced by Biran's ability to draw on so many different independent sources. Michal Biran's study of Qaidu is complemented by a treasure-trove of detailed notes and references, a healthy bibliography, simple but perfectly adequate maps, a glossary of Chinese terms and a most welcomely comprehensive collection of genealogical tables. Though regrettably the forty-six pages of enticing notes are clumped together at the end of the book rather than positioned so much more conveniently as footnotes, they are fully reflective of the amount of work and painstaking research that must have gone into this short but comprehensive study.