The first page wasn't a dry copyright notice. It was a cartoon of a rickshaw with IP addresses painted on it, and below it, a caption in Bangla: "জানেন কি? এই রিকশার চাকার মতোই নেটওয়ার্কিং-এ আছে রাউটিং টেবিল!" (Did you know? Just like the wheels of this rickshaw, networking has a routing table!)

His younger sister, Tisha, found him staring blankly at his laptop screen.

"Sir," he wrote, "আপনার বইটা না হলে, আমি পাস করতাম না। ধন্যবাদ।" (Sir, without your book, I wouldn't have passed. Thank you.)