Which type of document must be disclosed in a civil action?

In a civil action, the requirement for document disclosure is centered around the principle of relevance to the matters in issue of the case. The key point is that every document that is relevant and directly pertains to the issues being litigated must be disclosed. This encompasses any and all documents that could potentially support a party's claims or defenses, regardless of whether they are advantageous or detrimental to that party's position.

Documents that do not assist with the case are not necessary for disclosure as they do not advance the matters in controversy. The requirement does not limit itself to documents prepared by one party; both parties must disclose relevant materials. Moreover, documents from external jurisdictions are not automatically subject to disclosure unless they are pertinent to the current legal issues at hand. Thus, the correct principle is that every document related to the matters in issue must be disclosed, which ensures that both parties can adequately prepare and present their cases based on all relevant information.