The book that may, for HM, surpass all others as an exemplar of what can be achieved when the full potential of a handpress is exploited, is Leonard Baskin's Jewish Artists of the Early and Late Renaissance. We like it all the more for being completely fictional - "a small phantasy, inventing and imagining early Jewish artists and their work which happily answer a number of exceedingly difficult art historical problems" (The Work of Fifty Years, p. 111).
The book combines type set in a variety of shapes and printed on different handmade papers, the setting and printing both accomplished by Leonard's son Hosea, who at the time was a recent university graduate. It is a remarkable technical achievement (it also convinced him that he didn't want to spend his life repeating the effort, and he has since become a well-known dealer in early printed books). The artist described the design as "typographic play in the working of a form-binding cohesion between the etched portraits & their permutations & the shape-related geometry of the text" (p. 111).
The book combines letterpress text with intaglio portraits, one artist featured on each recto, accompanied by a brief biography. The intaglio plates are of various geometric shapes, typically more than one per artist, and combined with the text set in sympathetic shapes.
It appears that the intaglio printing was done after the letterpress, given the heavy plate impressions remaining. Setting the text to achieve both acceptable spacing and line breaks, while still creating the spaces in which the etchings will fall, must have taken ages (Baskin describes the compositional task as "hand and back cracking" in his notes to The Work of Fifty Years). No wonder Hosea didn't feel the need to repeat himself.
"This delicious jeu d'esprit was a proving ground, the means by which we attained mastery over the hand-press. Its delicate assault on sensibility is vested in the unexpectedness of the book's mise-en-page...Thus, "Unknown Dutch Artists," although beset with whimsy & trimmed with irony, was of consequent importance in determining the appearance & attitude of many later Gehenna Press books." (p. 98)
Printing with a handpress is a slow process. People who use a handpress as a pre-industrial oddity, or some belief in its moral purity, are not interesting. Conversely, people who use a handpress because its pace and limited output create opportunities to use materials and techniques that enable them to achieve result that just aren't feasible (or possible) using automated presses, are interesting. This is what Leonard Baskin, Hosea and the others involved with Jewish Artists succeeded in doing.
Jewish Artists probably will be the only title included in HM's handpress library in spirit only; it is an exceedingly rare Gehenna title, and when found, exceedingly expensive (a few more images & details about it and other GP items can be found here). But we have had the pleasure of being up close to the copy shown here several times, and have found much to be inspired by in its pages.