The first postage stamp, the Penny Black, was issued by Britain in May 1840 and pictured a young Queen Victoria. It was produced without perforations and had to be cut from the sheet with scissors in order to be used.
I started stamp collecting in the 1970's. My parents would save cancelled stamps that they received on envelopes and they would also order cancelled stamps that could be purchased. I couldn't wait to go to the mailbox and find a package of stamps to add to my album. The longer I collected, the more common it was to receive a stamp that I had already obtained. If the stamp I received was better than one that I had previously put in my book, I would use it as a replacement so that I would have the best quality of stamps possible. My stamp collection book from the 1970's contains postage stamps from all over the world.
I'm in pretty good company as a Philatelist -- or one who collects stamps. U.S. President Franklin Delano Roosevelt was a stamp collector, as was English singer, songwriter and peace activist John Lennon. King George V of the United Kingdom collected stamps, as did Freddie Mercury, lead singer of the band Queen. Why did I collect stamps as a boy? I believe it was because I was intrigued by the pictures, designs and colors of them. Remember, this was back in 1975 -- long before the Internet. Back then, at the age of 10, my exposure to the world was limited to what I would see in the Encyclopedia Britannica. Stamps were something that put into my hand an item that came from another part of the world. The images on the stamps were a window into another culture, and I thought that was quite interesting.
The most valuable U.S. stamp has an interesting story to it. It's the Inverted Jenny stamp of 1918.