The planning and design of library spaces is changing radically in the light of increased expectations, developments in teaching and learning, and the growth of electronic resources. The need for physical space in the age of the virtual library has been questioned, but in recent years there has been a plethora of bigger and better library buildings. This paper considers the drivers for change in library building design, the importance of good communication between librarians and architects, and the underpinning criteria for good design both of the building as a whole and of the fixtures and fittings within. Modern libraries must respond to social, pedagogical and technological changes, and librarians, in collaboration with architects and institutional administrators, must design inspirational and practical buildings fit for 21st-century use.