Art. 25 CISG
A breach of contract committed by one of the parties is fundamental if it results in such detriment to the other party as substantially to deprive him of what he is entitled to expect under the contract, unless the party in breach did not foresee and a reasonable person of the same kind in the same circumstances would not have foreseen such a result.
The Secretariat Commentary on Art. 23 of the 1978 New York Draft, predecessor to Art. 25 CISG, gives insight into the drafters' unterstanding on the eve of the 1980 Vienna Diplomatic Conference.
CISG-AC Opinion regarding Art. 25 CISG
CISG-AC Opinion No. 5 ‘The Buyer's Right to Avoid the Contract in Case of Non-conforming Goods or Documents’ (Rapporteur: Ingeborg Schwenzer), adopted by the CISG Advisory Council at its 9th meeting in Philadelphia (USA) in 2005
Overview of case law on Art. 25 CISG: UNCITRAL Digest
The UNCITRAL Digest on the CISG can be used as a starting point to discover the relevant case law on this article.