US Patent and Trademark Office (USPTO)The best place to learn about American patents and trademarks; the patent and appeals process ; the history of the USPTO; and the enforcement of intellectual property laws. Patents may be searched easily on this site by boolean keyword, patent number, inventor name, classification, and/or patent date, but the acquisition of patent images is often problematic and frustrating. Patents from 1790-1975 may be searched only by issue date, patent number, and US Classification.