"The Shadow Lines" is a novel that explores themes of memory, family, and national identity through the eyes of a young boy and his experiences growing up in Calcutta, India. The narrative is framed by two major historical events: the 1964 Dhaka Riots and the 1942 World War II. The protagonist's relationships with his family and his personal experiences are juxtaposed with these events, highlighting the complexities of identity, memory, and the lasting impacts of historical events on individual lives. The novel also delves into the arbitrary nature of national borders and the shadow lines they draw between people and their histories.

The book is a complex and thought-provoking exploration of friendship, identity, and the search for meaning. It follows the intertwined lives of two men, one a privileged banker and the other a mathematician from Bangladesh, as they navigate personal and global crises. Through their conversations and reflections, the book delves into themes of race, class, war, and the nature of knowledge, challenging readers to question their own assumptions and beliefs.