In their introduction, editors Sarah Blick and Laura D. Gelfand explain their title: the Pushmi-pullyu from the Dr Doolittle books is a creature with two heads that must come to agreement in order to attain motility. In the context of this volume, "Push me, pull you" characterizes methodologies that consider cooperative interaction between a viewer/user and an object. Each contributor explores how early audiences created reciprocal physical relationships with artworks. To place these questions in a theoretical framework, the editors offer a generally meaty and useful overview of various approaches that foreground reader/viewer responses.

The editors divide 34 articles into logical categories that fill two thick volumes. Most of the essays consider single objects or groups of related objects from the 12th-15th century. Given space constraints, I am unable to discuss them all. The full Table of Contents appears on Brill's website.

One group of articles addresses how sculpture, architecture, and other arts structure processions into and through churches. Fascinating is Kathleen Ashley's analysis about the physical rituals in which pilgrims to Santiago de Compostela participated: they touched the 12th-century doorway, embraced the polychromed image of St James, saw the relics, and received a stamp in their pilgrims' passports. Sarah Blick's article about what votaries did at the shrine of St Thomas of Canterbury is a feat of archival work and analysis (it turns out that they left mountains of wax votive body parts and candles). I assigned it to my students immediately, and I also assigned Vibeke Olson's article in which she hypothesizes that monks at Conques might have served as guides to the terrorizing and complex program of carved images, mediating between the pilgrims and the portals. Olson finds just the right balance between evidence and speculation. She takes risks, but they are well-grounded and help us shape the past. After reading Janet Snyder's contribution, you will pore over the depicted garments on 12th-century portal sculpture with fresh lenses, as you move beneath it. Mickey Abel's method is highly innovative: to discuss Romanesque portal compositions in relation to astronomical and medical diagrams inscribed in manuscripts.

Many of the essays treat images involved in pilgrimage, real or virtual. Because pilgrimage requires bodily involvement, the devotional practices around it lend themselves to interpretations considering ways in which they structure or invite interaction. Essays in this category include Henry Luttikhuizen's on spiritual pilgrimage in early Dutch painting; and Megan Foster-Campbell's on pilgrims' badges in books of hours, which she interprets as revisiting or even creating pilgrimages to local shrines. Some authors overenthusiastically claim their objects as tools for virtual pilgrimage. Problematic is Elina Gertsman's essay, in which the author implausibly argues that Vierge Ouvrant sculptures structured virtual journeys 'through the holy womb'. This essay begins inexplicably with an image of the Last Judgment tympanum at Autun before leaping to the Quelven Shrine Madonna, an object that opens to reveal compartments bearing scenes from the Passion. In my opinion, this garishly painted object, which the author unconvincingly dates to ca. 1500, is much later and does not belong in this book.

Indulgences played a part in stimulating interaction between images and votaries. Essays treating this theme include Walter Gibson's on early indulgence prints; Amy Morris's on German altarpieces; and Susan Ward's on an alabaster panel of the Mass of St. Gregory. All of the essays in this section consider the motif of the Gregorian Mass, one of the key indulgenced images of the 15th century, and each one provides a version of the story's origin myth (Gregory was performing mass one day when a miracle occurred ...). Readers should note that the Stoke Charity Mass of St Gregory that Ward discusses is made of limestone, not alabaster - no doubt an error introduced because travel funds for seeing works in the original are in such short supply. Amy Morris is to be commended for bringing to light some un(der)studied altarpieces, objects presenting lists of indulgences for display in public settings.

A codex, by its very format, demands physical interaction by its user: meaning heavily depends on the reader's part. At least three essays treat a sub-category of medieval studies that might be called 'manuscript margin studies', which consider how margins ask the reader/viewer to perform yet another feat. These include a co-authored essay by Robert Clark and Pamela Sheingorn treating marginal images as visual glosses, which require the reader/viewer to interact by toggling between different areas of the page. Margaret Goehring takes a new look at the Breviary of Eleanor of Portugal, where the painted borders reverse the ordinary primacy of the page, subordinating historiated initials and even full-page images to the marginal decorations.

One could argue that any visual work of art/object requires some degree of interaction in order to make meaning. It is not entirely clear why some of the essays belong in this collection, as they chronicle tangential or non-physical interactions with objects. The editors might have weeded some of these out.

What does one really want from an essay in this type of a compilation? Original archival research, in which newly discovered documents or facts are integrated into an existing art historical framework, and written in jargon-free prose, with full intellectual debts paid, including acknowledgments of images lent by other scholars. At least 75% of the contributions here manage this. These volumes have something for everyone studying late medieval piety and the widening gyre of "performativity." Individual essays or groups of them should appear on syllabi.

Kathryn M. Rudy