 In 1973 , when Lennon and Ono separated , Pang and Lennon had a relationship lasting over 18 months , during a time which Lennon later referred to as his " Lost Weekend . " Pang subsequently produced two books about their relationship : a memoir called Loving John ( Warner , 1983 ) and a book of photographs , Instamatic Karma ( St. Martin 's Press , 2008 ) . 
