Don't make me think!: a common sense approach to Web usability

Don't Make me Think by Steve Krug Although it's an "old" book (2009 edition), the content is still fully valid. Considering it speaks about the design of digital products, which is changing everyday, it contains some usability principles that almost never expire! I learned a lot from the many case studies and great examples it presents: they can help anyone, not necessarily designers, to follow those principles and save users some serious headaches! :)

-- Bahareh Taghavi