Architectural plan, ink line drawing on tracing paper, of the second floor of Main Library (now level 4 of Duhig Building). Title block has: job title of Alterations and Additions to Main Library; Interior architect J.P. Birrell; no job number; and undated.

Architectural plan, ink line drawing on tracing paper, of the first floor of Main Library (now level 3 of Duhig Building). Title block has: job title of Alterations and Additions to Main Library; Interior architect J.P. Birrell; no job number; and undated.

Architectural plan, ink line drawing on tracing paper, of the ground floor of Main Library (now level 2 of Duhig Building). Title block has: job title of Alterations and Additions to Main Library; Interior architect J.P. Birrell; no job number; and undated.

Architectural plan, ink line drawing on tracing paper. Drawing for lower ground floor with electrical details and furniture number, with pencil annotations. No title block, no job/drawing number, no date.

Architectural plan, ink line drawing on tracing paper. Title block: Alterations and additions to Main Library, 1st & 5th floors; University Architect is J.P. Birrell; job number is A2/46A; dated Aug 1965. It includes deletions and additions to flirst floor and additions to fifth floor.

Architectural plan, ink line drawing on tracing paper. Title block: Alterations and additions to Main Library, University Architect is J.P. Birrell, job number is A2, dated Nov 1965.

Architectural plan, ink line drawing on tracing paper, with toilet locations in relation to stairwells for Main Library. No title block, no title, no job number and undated.

Architectural plan, ink line drawing on tracing paper, for the existing lower ground floor of Main Library (now level 1 of Duhig Building). Title block has: job title of Alterations and Additions to Main Library; Interior architect J.P. Birrell; no job number; and undated.

Architectural plan, ink line drawing on tracing paper. Title block: Building is Main Library, University Architect is J.P. Birrell, job number is A2/47, dated Sep 1965.

Main Library was part of the Great Court buildings designed by Hennessy and Hennessy in 1935-1936. It consisted of two floors with a glass ceiling in the light well in the centre. Main Building was designed to be extended with an additional three floors, with high ceilings and a large light well in the centre. When the Library had insufficient space for students and books it was decided to go ahead with the extension of three more floors, as specified by Hennessy and Hennessy. Birrell proposed five additional floors instead of the three, the installation of passenger lifts, fluorescent lighting, and air-conditioning. Birrell was responsible for the internal arrangement and finishes. This file comprises 15 plans for alterations and additions to Main Library. Includes: sketch of lower ground floor (now Level 1), working drawings for 1st to 5th floors (now Level 3 to Level 7), stair details and compactus shelving.

Main Library was later known as Undergraduate Library; with the construction of Central Library in 1971 its name was changed to Duhig Building; and later, around 2000, to Duhig Tower.