Borries Schwesinger produced this superb book about form design.
The subject of the book was also the focus of Borries' dissertation earlier on in his career. He built upon his dissertation with more written and visual content in order to produce what I think is the only book worth reading if you want to learn more about forms. He talks about their history, design, and use. It's not common that people write about how designs are actually used by the general public but in this book it was unavoidable. So it's interesting to read what he says about how people use forms.
The book has a striking cover design. It's a pattern of alternating green diagonal lines with some low-key typography overlaid. He uses a thin stock for some of the first few pages that feature full-bleed images. Definitely something an all-round designer should consider adding to their book shelf.