The £20 million project will link Basil Spence's Sydney Jones Library, built in 1974, and the late 1960s Senate House, designed by Tom Mellor.
Both buildings will be adapted and refurbished as part of a larger scheme to create a combined central library facility for the university.
SEH's new link building will provide space for helpdesks and information points and will enable access to both buildings across all three storeys.
Once complete the three buildings will enclose a new urban space - dubbed the 'library plaza'. This square will boast a new café terrace and will replace the existing, steeply sloped forecourt to the Sydney Jones Building.
The project is scheduled to start on site in spring 2006.