Chapter 900
Chapter 900 covers prior art searching, classification systems, and examiner search obligations. Examiners must document searches and may search beyond primary classification. Prior art includes US patents, foreign patents, and non-patent literature.
Core Concepts
Examiner Search Obligation — MPEP 904 Examiner must conduct thorough search of prior art before issuing first Office Action. Search must cover all claimed subject matter. Examiner documents search in Search Notes. May search related classifications beyond primary classification. IDS citations from applicant must be considered.
Classification Systems — MPEP 905 CPC (Cooperative Patent Classification): joint US-EPO system, primary classification system. USPC (US Patent Classification): legacy system, still used for some searches. Examiners search both domestic and foreign patent documents and non-patent literature (NPL).
Prior Art Sources — MPEP 901 US patents and published applications. Foreign patents and published applications. Non-patent literature: journals, textbooks, abstracts, internet publications. Prior art date depends on type: patents = filing date for 102(e); publications = date of public accessibility.
Search Documentation — MPEP 719 Examiner must record search history in IFW (Image File Wrapper). Search notes identify databases searched, classification codes, keywords. Applicant may request search notes. Inadequate search can be basis for petition.
Key Rules
EXAM TIP
Prior art dating rules are frequently tested: US patents as prior art under 102(e) use the filing date, not the issue or publication date. Publications use the date of public accessibility. These different reference dates affect anticipation and obviousness analyses significantly.
Common Traps
Search Terms
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