In May 2015, a conference was held at Princeton University in honour of Anthony Grafton's sixty-fifth birthday. It brought to a small university town in central New Jersey many of Grafton's students, colleagues and friends from around the world. His doctoral students presented on aspects of his work. Not only an occasion to recognize Grafton's extraordinary and vast scholarship, it was also a celebration of his remarkable capacity for friendship, mentorship and generosity, which has enabled him to transform the historical discipline and inspire its practitioners in multitudinous ways.

So too starts this two-volume collection of essays: with a reminder that friendship, or amicitia, like an electric current, animates scholarly rapport to this day. For the sixteenth-century humanist Martin Crusius, friendship was a powerful force that ‘often pushes us to do things that we would otherwise have been slow to undertake’ (p. xv). None of the contributors here are Grafton's direct doctoral advisees; they are friends, colleagues and students who collaborated with him on various projects. Some essays recover the conversations which sparked their new research directions. They show how these exchanges bore fruit across disciplines, nationalities and academic ranks. Friendship was the very currency by which the early modern Republic of Letters operated at its most generous, and Grafton and his fellow scholars stand as a testament to its undiminished value in its modern analogue.

For the Sake of Learning begins with a short preface and Grafton's biography and bibliography, which frame the eminent scholar and his achievements and wide-ranging impact. The volumes contain fifty-six contributions organized around seven thematic sections: ‘Scaliger and Casaubon’, ‘Knowledge communities’, ‘Scholarship and religion’, ‘Cultures of collecting’, ‘Learned practices’, ‘Approaches to antiquity’, and ‘Uses of historiography’. Each segment reflects an area of Grafton's long-standing research activity. All touch on the history of knowledge and humanism, and many would easily fit into more than one thematic grouping above. Two reflective essays, by Lisa Jardine and Jacob Soll, appear in the epilogue. Because a thorough survey is beyond the scope of this review, I will spotlight two pieces per theme.

The first part considers Joseph Scaliger and Isaac Casaubon, humanists whose study has occupied Grafton throughout much of his life. In an intriguing essay, Dirk van Miert uncovers Scaliger's and Casaubon's strategies of concealing academic criticism in correspondence. Humanists discussed whether epistolary content ought to be censored in print and, if so, by whom; they also wondered about the boundaries between private and public. During the seventeenth century, van Miert suggests, commercial imperatives of publishing and scholarly considerations of historical fact trumped protecting authorial reputations. Tensions between a scholar's erudition and reputation are also explored by Mordechai Feingold. He shows that Scaliger was as respected for his learning as he was criticized by orthodox Calvinists for his historical approach to Scripture. Although Scaliger's work on chronology was admired, his stinging critiques won him few friends. Feingold urges further research into Scaliger's reception in England.

In a tour de force article in Part 2, Sarah Gwyneth Ross follows members of the Andreini family and their humanist personas as actors and authors. The Andreini transmuted their fluency in humanist discourses into cultural credibility and membership in the Republic of Letters, she argues. Their efforts ennobled the theatre as a school where audiences learnt erudite morality. Daniel Stolzenberg challenges Noel Malcolm's interpretation of Athanasius Kircher as a correspondent on the margins of the Republic of Letters. Kircher was a ‘boundary spanner’ whose letters expose vast networks of correspondents, at the centre and periphery, who supplied him with information for his books. Effective studies of the republic, Stolzenberg argues, must examine communication strategies in letters in light of the books that resulted from such exchanges.

Part 3 unpicks the connections between scholarship and religion. In a brilliant study of misreading, Arnoud Visser gives us an impassioned Luther arguing with Erasmus in the margins of the latter's edition of the New Testament. Luther construed Erasmus's philological commentary as humanistic arrogance and his humour as mockery and, therefore, as signs of his unbelief, argues Visser. In his essay, Jonathan Sheehan traces the history and early modern uses of the sacrificing king (rex sacrorum) – an institution with power over sacred rituals that survived into the ancient Roman republic. The sacrificing king allowed humanists, like Lipsius and Grotius, to imagine multiple solutions to the relationship among political, legal and religious authorities.

Part 4 turns to cultures of collecting. William Sherman tours the book collection of Hernando Columbus, Columbus's second son. A vast library, counting over fifteen thousand books and three thousand prints, the Biblioteca Colombina was intended as Spain's first national research library. Hernando hoped his library would make available all human knowledge and become a state institution. Thomas DaCosta Kaufmann traces the interplay between art and science at the Dresden Kunstkammer in an age of global travel and commerce. He shows that Renaissance painters and sculptors consulted natural histories and Thierbücher of exotic animals, scrutinized live and stuffed specimens, and often collaborated with naturalists in preparing studies of birds and other creatures.

Part 5 encompasses ways of acquiring, testing and advancing knowledge. In a fascinating essay, William Newman disputes interpretations of Robert Boyle as a Baconian experimenter who eschewed supernaturally derived knowledge. Boyle relied on English disciples of Van Helmont whose epistemology and practices included visionary dreams and spirits directing the success or failure of experiments. He also managed a long-term experimental programme to produce the alkahest through correspondence with Helmontian chymists in Boston. The focus of Arthur Kiron's essay is the ledger book of Sabato Morais, the Italian-born Jewish cantor and religious teacher who immigrated to Philadelphia in 1851. Morais's scrapbooking, Kiron argues, was a social practice and attempt to leave a legacy of his life's work.

Part 6 surveys humanism's revival of antiquity. In a compelling contribution, Hester Schadee compares the materiality of ancient codices to relics. She merges a study of humanist rhetoric with sensory history, by linking the Catholic doctrine of resurrection and relic worship with the humanistic desire to recover all manuscript fragments of an ancient author as a way of restoring him to life. James Hankins inspects how the humanist Cyriac of Ancona interpreted the cycle of constitutional degeneration and renewal invented by the ancient Roman historian Polybius. Polybius generally favoured kingship as the best form of government, but also endorsed democracy. Like Polybius, but unlike other humanists, Cyriac praised democracy as a positive and practical system.

In Part 7, writing histories sometimes meant writing propaganda. Virginia Reinburg's subjects are authors of French Catholic shrine books who transformed seventeenth-century shrines into places with ancient origins. Invented antiquity became a marker of shrine authenticity, and helped to attract the patronage of bishops and noble families. Paula Findlen's superb essay reconstructs the forgeries of Alessandro Machiavelli, an eighteenth-century lawyer and medievalist who invented a female jurist, Bitisia Gozzadini. He spun a medieval history of learned women at Bologna in the hopes of bolstering his patron's daughter's attempt to obtain a university law degree. Machiavelli's fabrication was ‘a manifesto of eighteenth-century feminism forged in the Bolognese archives’ (p. 876).

For the Sake of Learning is more than a Festschrift for Anthony Grafton. It honours a giant who reshaped in profound ways how we write about early modern scholars, their methods and the ateliers where they were active. It also shows how contemporary historians and other humanists have advanced the ‘Grafton method’ and taken scholarship in new, surprising directions. These authors scrutinize instances where tradition survived and amalgamated with innovations, and exercise a deep understanding of classical philology. Some introduce rare manuscripts and offer original interpretations; others challenge historical understanding of more familiar material. Forgotten figures like the German Egyptologist Georg Ebers and Italian Jewish cantor Sabato Morais are remembered. Prominent natural philosophers Bacon and Boyle are read in fresh ways. What is more, the essays are written in elegant prose. Not all are in English, however: four essays appear in German and one in Latin; some lack translations of their foreign-language quotations. In that respect, the ideal reader should be a bit of a Graftonian polyglot. This collection contributes new material to the history of knowledge and humanism, and is the fugue to the prelude of ‘Graftonfest’ 2015.