Not long ago traveling humans only carried their necessities with them: food, clothing, passports, kids. If you wanted to talk with someone, you found a phone booth; to listen to music or catch up on the news, turn on the car radio; to see a movie, check the listings in the paper and drive to the neighborhood theater.

That was then, this is now. Somewhere along the line the definition of “necessities” changed to include music. Sony’s introduction of the transistor radio in the 50s—the product on which they launched the company—was radical. Suddenly every teenager on the face of the earth had to have one. The sound was tinny and you needed to carry spare batteries, but transistor radios were “cool.” Even in the 50s, being cool could sell ...

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