What are Preliminary Proceedings ("Diligencias Preliminares") in Spanish Civil Law?
The preliminary proceedings could be defined as those proceedings that serve to prepare a trial. Therefore, the preliminary proceedings are planned in order to facilitate the possibility of obtaining the documentary information necessary for the presentation of the lawsuit by whoever is entitled to do so.
The Supreme Court declares in an Order of 11/11/2002 that "Preliminary proceedings can be considered as the set of actions of a jurisdictional nature for which the competent Court of First Instance is asked to carry out specific actions to resolve the essential data so that the future trial can be effective".
Let's see it with an example: a person who is an agent for a sales company and who gets paid bonuses out of the deals she's able to complete is going to sue the company that has hired her, but she does not know the company's accounting to be able to detail the exact amount that corresponds to her.
In this case, before filing the lawsuit, her lawyer can use the preliminary proceedings so that the company can show previously the accounting in order to verify everything related to the commissions so the lawyer can file the definitive civil lawsuit including the corresponding evidence.
Preliminary proceedings in civil cases are regulated in article 256 of the Spanish Civil Procedural Law.