The first novel, Bayn al-Qasrayn, is named after the medieval Cairo street in the Gamaliya district where the strict socially conservative protagonist, Ahmad 'Abd al-Jawad, and his family live.
The trilogy follows the life of the Cairene patriarch Al-Sayyid (Mr.) Ahmad 'Abd al-Jawad and his family across three generations, from 1919 – the year of Egyptian Revolution against the British colonizers ruling Egypt – to almost the end of the Second World War in 1944.
To Kamal, 'Abd al-Jawad's youngest son, Mahfouz admits that he gives him some features of himself, as they both got a BA in philosophy from what is now the University of Cairo and have problems with profound contradictions they discern between religious principles and the scientific discoveries of the West.
Throughout the trilogy, Mahfouz develops his theme: social progress will be the inevitable result of the evolutionary spirit of humankind.
Time is the major leitmotif in all three books, and its passage is marked in literal and symbolic ways, from the daily pounding of bread dough in the morning, which serves as an alarm clock for the family, to the hourly calls for prayers that ring out from the minarets of Cairo.