Modifies a noun

• knowledge: They were simple, honest, moral people who had firsthand knowledge of the facts.

• account: The final session was a firsthand account of " The Patient's Experience of Bristol.

• experience: I have firsthand experience being a bisexual in John's.

• information: So local people provided firsthand information and also security.

• observation: Nor is there any consideration of Milton Viorst's nearly contemporaneous, firsthand observations.