I tend to split design books into two related but somewhat distinct clusters: books about visual or aesthetic design, and books about engineering or technical design. Of course, it's not a clean split (architecture in particular strongly combines the two), but some books are clearly more on one side or the other.
For the engineering-design side, two good books, imo:
Herb Simon's classic Sciences of the Artificial, which approaches design from the lens of an AI researcher trying to figure out what design really is, partly to develop it into a science of design, and partly with an eye towards formalizing a model of design that a computer could use: http://mitpress.mit.edu/catalog/item/default.asp?ttype=2&...
Designerly Ways of Knowing by Nigel Cross, which positions design as a third kind of inquiry, neither fully science nor fully humanities, but a kind of constructive investigation of objects and their properties: http://www.amazon.com/gp/product/3764384840/ref=as_li_ss_tl?...
For the engineering-design side, two good books, imo:
Herb Simon's classic Sciences of the Artificial, which approaches design from the lens of an AI researcher trying to figure out what design really is, partly to develop it into a science of design, and partly with an eye towards formalizing a model of design that a computer could use: http://mitpress.mit.edu/catalog/item/default.asp?ttype=2&...
Designerly Ways of Knowing by Nigel Cross, which positions design as a third kind of inquiry, neither fully science nor fully humanities, but a kind of constructive investigation of objects and their properties: http://www.amazon.com/gp/product/3764384840/ref=as_li_ss_tl?...