At some point in time, Alan Grant got married to an unidentified person, but died later. It is unknown of her cause of death, and she is only mentioned once by Dr. Grant while talking to Tim as they tried to make their way to the Visitor Center.
“Are you divorced?” “No,” Grant said. My wife died a long time ago.” Quote found in the Jurassic Park novel: Fourth Iteration – In The Park (page 235 paperback edition)
