Relatives of the extremely low key fashion and society photographer Bill Cunningham were shocked to find a secret memoir among his belongings.

The New York Times staff photographer died in 2016 aged 87, after a prolific near-40 year career with the newspaper.

It is not clear when Cunningham, who is fondly remembered for his "On the Street" column below, wrote the book.

“It seems so unexpected,” said Christopher Richards, an editor at Penguin Press who acquired the book at auction. “He really didn’t divulge anything about his life to his friends and his colleagues. He was so private. I think it was a shock.”

Cunningham had called the memoir, which included multiple drafts and notes, “Fashion Climbing”.

Bill Cunningham, the celebrated (and beloved) fashion and society photographer for @nytimes, left behind a secret memoir.
It’s called “Fashion Climbing.”

— Clifford Levy (@cliffordlevy) March 21, 2018

The title is a reference to his staunchly Catholic upbringing in a "lace-curtain Irish suburb of Boston".

Cunningham's extremely religious mother disapproved of his flair for fashion.

According to New York Times writer Matthew Schneier, one of the pages in the books shows "a little doodle of a young Bill ascending a ladder, and added a line attributed in the book to his mother: What will the neighbors say?"

The book chronicles Cunningham's early passion for style, his service in the Korean War, his foray into the millinery business, and his beginnings as a journalist.

“It’s a crime families don’t understand how their children are oriented, and point them along their natural way,” Mr. Cunningham writes of his stifling childhood in the memoir. “My poor family was probably scared to death by all these crazy ideas I had, and so they fought my direction every inch of the way.”

In the book's emotive opening, Cunningham recalls a painful early childhood memory.

“There I was, 4 years old, decked out in my sister’s prettiest dress. Women’s clothes were always much more stimulating to my imagination. That summer day, in 1933, as my back was pinned to the dining room wall, my eyes spattering tears all over the pink organdy full-skirted dress, my mother beat the hell out of me, and threatened every bone in my uninhibited body if I wore girls’ clothes again.”

The book is stated to be published in September; just in time for New York Fashion Week.

The trailer for the 2011 documentary "Bill Cunningham New York" which charted the iconic visionary's career can be viewed below.