Free & open collections

Digital libraries & archives

When Halvorsen Library does not hold something, these are where it sends you first. All are free to read.

• Open Library — a page for every book ever published, with millions borrowable online (Internet Archive)
• Internet Archive — books, audio, video, software, and the web, archived and open
• HathiTrust Digital Library — a shared research library of digitized volumes from academic libraries
• Digital Public Library of America — photographs, manuscripts, and records from thousands of U.S. libraries and archives
• Project Gutenberg — 70,000+ public-domain e-books, carefully proofread
• Library of Congress — digitized collections, Chronicling America historical newspapers, and primary sources
• Smithsonian Open Access — millions of images and 3D models, released to the public domain
• Europeana — cultural heritage from museums, galleries, and archives across Europe
• Wikimedia Commons — freely reusable images, diagrams, and media

Open textbooks & courses

The course-materials estimate in your tuition is close to zero partly because faculty adopt open texts. Start here for a subject you want to preview or review.

• OpenStax — free, peer-reviewed college textbooks for high-enrollment courses
• Open Textbook Library — a reviewed catalog of open textbooks across disciplines
• LibreTexts — openly licensed textbooks and lab manuals, especially strong in the sciences
• OER Commons — a search engine for openly licensed teaching materials
• MIT OpenCourseWare — lecture notes, assignments, and exams from MIT courses
• Khan Academy — video lessons and practice from arithmetic through introductory college subjects
• Saylor Academy — free self-paced courses, some with low-cost credit-recommended exams

Open research & scholarship

For a literature review, a thesis, or just chasing a citation. Librarians can show you how to use these well.

• arXiv — preprints in physics, math, computer science, and related fields
• bioRxiv & medRxiv — preprints in the life and health sciences
• PubMed Central — a free full-text archive of biomedical and life-sciences literature
• Directory of Open Access Journals — a vetted index of quality open-access journals
• CORE — the world's largest aggregation of open-access research papers
• OpenAlex — an open index of scholarly works, authors, and institutions
• Semantic Scholar — AI-assisted search across scientific literature
• Unpaywall — a browser extension that finds legal free versions of paywalled papers
• Zenodo — a CERN-hosted repository for datasets, code, and papers, with DOIs
• Open Science Framework — project management, preregistration, and sharing for research
• ORCID — a free persistent identifier for researchers — set one up before your first publication

Getting help

A subject librarian can show you how to search these efficiently, how to tell an open-access journal from a predatory one, and how to get a paper the library does not have through interlibrary loan — usually within a day or two. See library services or the full open resources guide for data and tools.