Published in Brill's Companions to the Christian Tradition series, the declared mission of which is to be ‘a series of handbooks and reference works on the intellectual and religious life of Europe, 500–1700’, Joan Mueller's Companion to Clare of Assisi fulfills that charge. In seven chapters and a valuable appendix of Clare's writings newly translated (including her four letters to Agnes of Prague and her forma vitae), the text leads the reader by the hand through the not unproblematic history and historiography of Clare and her Poor Sisters. This is followed by close analyses of her letters, paying special attention to Clare's use of the Legend of Agnes of Rome (of which a useful translation by Julia Fleming is provided), and her monastic rule. The rule or forma vitae, as Clare called it, is significant because it is the first in western history written by a woman for a female community of enclosed nuns. Mueller claims that it is ‘legislation that is truly feminine in character’ (p. 210). I wish I knew what that meant in practice; gender is a useful category of historical analysis and it would have been helpful, especially given Mueller's deep knowledge of the rule, had a gender analysis been incorporated systematically in her exposition of the rule. The other place where I wished for more was in the discussion of recent historiography, particularly the Italian and German debates about the authenticity of a number of texts written by or relating to Clare. Here I am thinking of the Testament and the Innocentian ‘Privilege of Poverty’, both of which scholarly consensus now agrees were forged in later centuries. Mueller is admirably up-to-date on the recent debates and it might have been profitable for her student readers to have been apprised of some of the highlights of the recent discussion. Those texts once served to bolster Clare's link to the Franciscan notion of poverty; but notwithstanding their expulsion from the canon, the Clare who emerges from Mueller's study is a strong-willed woman, unyielding in her devotion to voluntary poverty, a privilege for which she fought vehemently and which was bestowed on her reluctantly by Pope Gregory ix. As represented by Mueller, a Franciscan sister herself, Clare was no shrinking violet when poverty was at stake. Indeed, modifiers such as subversive or rebellious are not misplaced when applied to Clare in this regard. The smoking gun here is Clare's second letter to Agnes of Prague, a contemporary Bohemian princess who founded a convent on the model of Clare's San Damiano and whose struggle with the papacy over the rights of poverty echoed Clare's own. In Mueller's close reading of that letter, we see that Clare's is no vague exhortation to embrace poverty, it is marching orders for Agnes to stand tall against the pope: ‘Indeed, if someone [read Gregory ix] tells you something else or suggests anything to you that may hinder your perfection or seems contrary to your divine vocation, even though you must respect him still, do not follow his advice. Instead, poor virgin, embrace the Poor Christ’ (p. 145). Clare never surrendered to the efforts of a series of popes to impose property on her; here she was counselling Agnes to stand her ground and do likewise. Clare was steadfast in her opposition to property, not only on ideological grounds but also because she seems to have been aware of the inevitable problems it entailed. Mueller highlights how Clare's forma vitae forbade accepting old and infirm women into the convent as to do so predictably meant accepting endowments for their care which were then open to litigation by family members or heirs. Indeed any property was subject to litigation, taxes and tithes, which was why Gregory ix, when trying to establish a Clarissan Order out of all the disparate communities that had affiliated themselves with Clare and San Damiano, put those foundations under the control of the Holy See, making them less vulnerable to local financial predators. Clare's commitment to poverty and a nuanced explanation of what that signified in the thirteenth century is Mueller's achievement in this volume. Like Beatrice in the Paradiso, she provides a sure-footed guide for novices and students who need an accessible introduction to Clare of Assisi, her writings and her historical context.