Complex sentence: The opening of the foundation featured June and Helmut's portraits from their joint 1999 publication, "Us and Them"; the book features portraits that June and Helmut had taken of one another, as well as photographs that they had both taken of certain celebrities.
Split into simpler sentences: The opening of the foundation featured June and Helmut's portraits from their joint 1999 publication, "Us and Them". The book features portraits that June and Helmut had taken of one another, as well as photographs that they had both taken of certain celebrities.