Search the text inside digitised American newspaper pages held by the Library of Congress. This reads what optical recognition took off the scanned pages, so it finds a phrase that appears nowhere in a title or a catalogue record. Put a phrase in double quotes to match it whole; without quotes the words are matched separately, which finds far more. 'total' counts the pages that match, and they page: ask for page 2, 3 and so on to see beyond the first answer. It is not a count of how many times the words occur. Each match names the newspaper, the date, the leaf of the issue and the state it was published in, and 'source_url' opens that leaf with the query applied. 'location' keeps to papers published in one state, 'publication' to a single paper, and 'year_from' with 'year_to' to a span of years. A filter matching nothing is dropped and the answer says so. The Library returns the opening of a page's text with each row rather than the whole page, so the searched words are often further down than the excerpts reach: 'words_located' says which of the two happened for each match. Use search_items instead when looking for a work by its title, creator or subject.

Search the Library of Congress catalogue: books, photographs, maps, recordings, films, manuscripts, sheet music and newspaper titles. 'media_type' is required, because the Library keeps a separate catalogue for each kind of thing. This matches titles, creators and catalogue descriptions. It does not read the text inside a scan; use search_newspapers for a phrase printed on a newspaper page. 'subject', 'location', 'language' and 'collection' take the words the Library itself uses, as they appear on the rows this tool returns. A filter matching nothing is dropped and the answer says so. By default only material with a digitised copy is returned; set 'online_only' to false to take in records the Library holds on a shelf alone. Every row carries an 'identifier', which get_item takes.

Read one Library of Congress record by its identifier, as returned by search_items or search_newspapers. An identifier can carry slashes: a single newspaper issue is named by its paper, its date and its edition together. Sections are opt-in: 'basic' is the default and covers what a description needs. 'citations' returns the ready-made citations the Library publishes for the record. 'resources' lists the served copies, such as page images and downloadable files. 'full_metadata' returns every field the Library publishes for the record, which is large and rarely needed. A long description paginates: when 'next_offset' is not null, call again with 'offset' set to it.

List the digital collections of the Library of Congress: bodies of material a curator chose, described and published together. Use it to see what is there before searching, since a collection names a corpus that a query would have to guess at. 'collection_filter' on each row is the wording search_items takes as its 'collection' argument. 'item_count' is how many records the collection gathers, which is the size of the corpus rather than the number of rows here.