Libraries were a life motif in Aalto's oeuvre, a theme to which he returned time and again throughout his life. His library plans thus provide a coherent summary of his development.

His first significant effort in the field was the library wing Included in his 1923 competition entry for the Finnish Parliament House. In it Aalto tried out a highly original cross between o cubiclized Classical theatre cavea and on open-shelf system directly accessible to the public. This motif was transformed in the 1927 competition entry for the Viipuri City Library into his first sunken 'book pit,' which reappeared in modified form in most of his loser library designs. The book pit suggestively alludes to literature as man's underlying spiritual foundation; librarians, however, have criticized it is unfunctional and laborious.

AaIto's Classicist competition design of the Viipuri library still relied on the example of Gunnar Asplund but the final plan of 1933 introduced a series of functional "inventions" in the plan itself, while stylistically pointing to Walter Gropius and Le Corbusier. Viipuri library was Finland's first Functionalist library building.

In his next competition design, the 1937 entry for an annex to the Helsinki University library, AaIto confirmed his opposition—already evident in the Viipuri library auditorium—to the rigidity and geometric formality of Rationalism. In the Jyverskyla University library from 1953-55, he had the stacks rise, manlike, from the lending counter at the bottom level: this complicated solution, however, unfavourably affected the building's height. When designing the Seinajoki City library in 1958, AaIto discovered a solution on which he based most of his later library plans: a fan arrangement of the book collection, placed like on annex at the long end of o rectangular building volume containing the offices and other subsidiary functions. This plan solution could be combined with smaller book pits, as in Rovaniemi City library, or it could take the form of concentric, theaterlike terraces on a sloping site, as in the Mount Angel library in Oregon.

From the 1950s on, Aalto's efforts to bestow or his cultural buildings a free-form, sculptural overall impact by having the exterior mirror the asymmetry of the interior (as in the Helsinki House of Culture) reflected in some of his library designs, such as the 1966 plan for Kokkalo Library.

For a 1927 competition to design the Viipuri City library Aalto designed the winning entry, but reworked it repeatedly before it was built. Abet the City Council decided on the new placing of the library in Torkkeli park in autumn 1933. Aalto dialled the final version and signed the drawings in December 1933. Construction got under way in 1934, and the library was inaugurated on October 13. 1935. As planned earlier, the facades were finished with white rendering into Corbusier style, but the collagelike overlapping of building volumes and the new location called for a redisposition of rooms. The staircase can be seen through a gloss wall from the entrance hall, which merges with a long auditorium; the children's library, lending room, reading rooms, and basement stacks ore more lightly integrated into the main volume. The original Asplund-style 'book pit' still forms the main entrance so the lending room and its centrally placed 'librarian's' watchtower." AaIto reverted to his original idea of top-lighting for the lending and reading rooms, though this time he solved the problems of winter snow and direct sunlight with rows of round "barrel skylights" that rise above the roof surface (an idea used previously by Aalto for some basement storerooms in the Turon Sanomat building). This meant deleting the rooftop garden Other important innovations included a generous use of light, unpainted wood panelling, irregular serpentine lines in the interiors, and specially designed, functional light fixtures to make up for the auditorium's acoustically unfavourable elongated shape. Aalto developed the acoustic ceiling design of his 1930 competition entry for Tehtaanpuisto Church, using on apparently free—but in fact quite uniform—undulating form. The convincing overall grasp, the density of ideas, and she core token with every detail guarantee the Viipuri library pride of place in Aalto's pre-war output.

In an English manuscript in the AaIto archives, Aoki, explains his solutions to the problems of lighting and acoustics in the Viipuri library: 'The ceiling (of the reading rooms and lending room) has 57 round, conical openings, 1.8 meters in diameter, which function as skylights. The principle is as follows: the depth of the cones ensures that no light rays can penetrate of on angle of 52' or less. Thus the lighting is indirect oil year round. This achieves two goals: first, the books are protected from direct sunlight, and second, she reader is not disturbed by shadows or sharp light, whatever his position in relation to the book. The inner surfaces of the cones reflect daylight in such a way that the rays from each spread like a diffuse cluster over a large floor sun face. Every seat in the rending room, receiving light from several cones, is thus bathed in a composite light.

"The ceiling of the auditorium consists of joined wooden slots (with o total surface of 58 square meters), which disseminate sound, particularly speech at close quarters, in an acoustically advantageous way. Since debate is as important as lectures, audibility is not merely in one direction, as in concert halls. My acoustic construction is aimed of making every point in the auditorium equal as a transmitter and a receiver of words spoken at normal loudness over the floor. I consider acoustic problems to be primarily physiological and psychological, which is why they cannot be solved by purely mechanical means.”