Title 35 of the US Code (35 US Code) sets forth the requirements for patentability of an invention, and the requirements have remained largely stable since around 1952, with changes primarily due to more recent judicial interpretation and legislative changes implementing international harmonization due to international treaties such as GATT (which changed our system from a first to invent to a first to file, and brought about 18 months publication of US patent applications, as the default if foreign filing, or in the absence of filing of a nonpublication request for nonforeign filed applications). The requirements of patentability as outlined in title 35, for a given invention, include:

• Section 101 – Utility – an invention must be a useful, article of manufacture, process or improvement,  and since the Mayo vs. Prometheus and CLS Bank vs. Alice Corporation series of decisions, must be found to claim significantly more than any Abstract Idea, the present standard is more strict than earlier interpretations
• Section 102 – Novelty – an invention’s combination of elements of the broadest independent patent claim must be new, it must not have been previously disclosed, published, taught or have been anticipated by a prior printed publication, or offered for sale more than one year before filing for a patent, among other forms of so-called “prior art”
• Section 103 – NonObviousness – an invention cannot be deemed obvious in view of prior art, and there cannot have been a teaching of a motivation to combine two or more references to render the invention obvious to a “person having ordinary skill in the relevant art” (PHOSITA), i.e., an invention must include more than an insubstantial difference from the prior art, and secondary indicia of nonobviousness may be considered, including, e.g.,, commercial success of a claimed embodiment, a teaching away of the applied references, a solution to a longfelt, unmet need, among other factors
• Section 112 – Disclosure – to protect an innovation, an inventor must disclose or make open (“patent”) their idea by providing a patent application, which meets the additional requirements:
  
  • Section 112(a), (formerly 112, 1st paragraph)
    
    • Written Description – detailing support for the claimed invention, which may include drawings and a textual specification, and
    • Enablement – the description must enable the person having ordinary skill in the relevant art (PHOSITA) to make & use the claimed invention(s) without undue experimentation
    • Best Mode – the preferred embodiments contemplated by the inventor at time of filing must be disclosed in the Specification.
  • Section 112(b), (formerly 112, 2nd paragraph) – requires that the patent application include at least one claim, which is set forth with sufficient particularity and definiteness as to be clear, with proper antecedent basis of  claim elements for elements claimed with leading definite grammatical articles (“the” or “said”)
  • Section 112(f), (formerly 112, 6th paragraph) – allows for claiming using the functional form of means plus function claims – i.e., claiming  “a means for” or “a step for” performing a function (normally in the form of a gerund verb, i.e., ending in “ing”), however this claim form is generally discouraged today, as it is read narrowly to cover only “disclosed structure” and equivalents of that disclosed structure. Non-means plus function claims may be interpreted to cover a more broad scope of protection, which may include a broader claim construction under the “doctrine of equivalents” which may be broader than only the disclosed structure, if not otherwise barred, and for articles which perform substantially the same function, in substantially the same way, to accomplish substantially the same result as the claimed apparatus.