Some 25 years ago, I sat on those rickety wooden stools and discussed the same issues Mr. Roy wrote about in his blog, Mukto-mona (Free Mind) and his recent book, “The Virus of Faith.” We students openly proclaimed our atheism. We probably provoked some strong reactions, but we did not fear for our lives. We were proud of the Bengali tradition of secularism, unique to the Indian Subcontinent.

Bangladesh has changed. The expansion of the garment industry and the rise of microfinance and community development banks put an end to the stereotype of Bangladesh as a “basket case.” But economic empowerment also brought mass access to information. Today the disenfranchised and disgruntled can identify themselves with extremists anywhere in the world. What is their common identity? Religion.

When India was divided in 1947, East Bengal became part of Muslim Pakistan purely on the basis of its religious majority. A year later, Urdu was imposed as the national language. The Bengali language has always been linked with secular Bengali nationalism. Protests followed, and on Feb. 21, 1952, the Pakistani police opened fire on students at Dhaka University. That day — perhaps the beginning of the conflicts that culminated in the 1971 war of independence — is remembered every year in Bangladesh and in the Indian state of West Bengal, and the monthlong book fair is one of the commemorative events. When I tried to visit the fair just a few days before Mr. Roy was killed, I couldn’t make it through the crowds at the entrance to the university campus.

I had gone back to Bangladesh with two of my children so they could experience the sounds and colors that I grew up with. The first sign that things had changed was at Heathrow, when an attendant at the Bangladeshi airline desk said that we would not be allowed to enter the country because of the Israeli stamps on our British passports. I explained that I had visited with the same passport before, and we entered Dhaka without any hiccups. My confidence in Bengali liberal-mindedness thus restored, the children and I got in a motorized rickshaw, headed for the port of Sadarghat.

On the way, my 13-year-old daughter observed, “I thought it would be much more colorful. Are there no women in Dhaka?” Looking around, I realized that most women were covered in black burqas or hijabs — a style that I had seen in such large numbers only in the Middle East. Many of their male companions wore long white dishdashas and skullcaps.