The field and practice of international law of foreign investments has developed significantly during recent decades. Foreign investments across the world benefit from the existence of standards of protection guaranteed by the net of thousands of investment treaties, mostly bilateral (BITs). Foreign investments are typically represented by long-term commitments in a foreign country, thus requiring assurances of protection in the host State. BITs concluded between States provide investors with generous standards of protection, such as the so-called full protection and security clauses (FPS), fair and equitable treatment clauses, clauses addressing expropriation or compensation for losses clauses that address specifically armed conflicts, civil disturbances and other events (war clauses). However, also non-precluded measures clauses (NPM) are included in many BITs, and if successfully invoked, particular measures of the host State may be exempted from the scope of the BIT protection. Substantive standards of protection are bolstered by a distinct feature of investment protection—dispute settlement mechanisms allowing foreign investors to raise claims directly against States on the international level and seek compensation for losses. As States typically possess assets outside their own territory (such as shares in private companies or commercial property), enforcement of investment arbitration awards can be quite effective, especially through the operation of the New York Convention. That makes the field of international investment law (IIL) an important and potentially effective source of protection for foreign investors, at least in comparison to other fields of public international law.