The notebook is also a valuable tool for the inventor since it provides a chronological record of an invention and its reduction to practice. Each entry must be signed and dated by a witness. The witness should not be someone with a conflict of interest (such as a research partner). If an inventor ever has to go to court to prove he or she was the first to invent, then the witness would be called to the stand to testify that the signature is theirs and they signed that page on that date.