Finders Keepers

Question:

A friend of ours borrowed some books and then lost them. She replaced the books at her own expense and a week later found the original ones. She would (naturally) prefer to return the new books to the shop where she bought them, but in the meantime we have written our name into the new books. My guess is that the new books belong to us and the original books now belong to her. Am I correct?

Answer:

Yes, you are correct. By compensating you for the borrowed books when she did not know they were in her house, she acquired them. Even if you had not written your name in the new books, should you have wanted to keep them you would have had the halachic right to do so. You would not have had to let her return the books to the store and accept your original books back.

Her acquisition is also final. If she had found the borrowed books after buying you new copies and then you had demanded your original books back – let's say because of notes you had written in them – she would not have been required to return them to you. If the price of the borrowed books had gone up (perhaps due to your notes) after she had bought you replacements and later they were found in her home, she would benefit from the profit and you could not demand your original books back.[1]

If, however, she knew the books were in her house and still bought you the other books (this might happen if she wanted your books because of the notes), you could reclaim your original books.

In most circumstances the borrower acquires the borrowed item after compensation, as mentioned earlier. However, there is an exception to this rule. If she did not pay on her own but the beis din intervened and forcibly collected payment from her after assessing her possessions, the transfer of those assets to the lender is not necessarily a final transaction. If she subsequently found the books in her home, she could demand the bought books back and force you to take the used ones back, since she had only begrudgingly gone along with the ruling, which it is now obvious was done in error. Eventually it had become clear that the items had always been in her possession and if that had been known to the beis din earlier, the beis din would not have seized her assets. Therefore, the ruling of the beis din can be reversed. Similarly, if you wanted, you could demand your original books back.[2]

In your situation, the borrower recognized her own responsibility and willingly came forward to pay for the item she thought was lost. Compensation offered willingly is considered a binding transaction and irreversible by one party only. Furthermore, even if she had refused to pay and a dayan ordered her to do so (but did not have to seize her assets since she complied with the ruling), and then the borrowed item was found, neither party can unilaterally reverse the transaction. She is considered to have acquired the borrowed item with her compensation and can hold onto the borrowed books if she likes. Similarly, she cannot insist that you return the new books and accept your old books back.

BookID: 4 Chapter: 295