13 of 27 volumes published, with 34 of 92 sheets placed. A title opens the volume's page, with its catalog record and every scan. View opens its placed sheets over today's map in Allmaps; JSON is the IIIF file behind them. Images chooses whose scans they draw: Chronoscope's faster copies, or the Library of Congress's originals.
Not every page is placed, or placed accurately: please report problems. Missing a volume, or pages of one? Look for it on OldInsuranceMaps.net, or georeference it by hand there. If a volume doesn't load on your phone, switch Images to loc.gov, or try a desktop browser.