Probate research deals with finding heirs and proving their right to an inheritance. In some estates, there may be no known heirs, or there may be missing heirs whose names are known but their contact information is not. Succession law determines who a person's legal heirs are. There also may be known heirs from one part of the family, but another part of the family may be unknown In other cases, an heir may not be a family member, but someone who has been named as heir in a last will and testament. Named heirs can also be missing, or have predeceased the testator, leading to the need for probate research. In all these instances, professional probate researchers work to trace the next-of-kin, or the named heirs, in the case of a last will and testament.