CAMBRIDGE (CBS) – It’s another sign that we’re getting older – 40 years ago today (Tuesday), the rock band Led Zeppelin released it’s now classic fourth album.

The untitled record- referred to as “Led Zeppelin 4” includes classics such as Black Dog, Rock and Roll, and of course Stairway to Heaven.

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Stephen Davis lives in Cambridge. He toured with Led Zeppelin and writes about it in his new book, LZ-’75.

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His stories include a riot that actually kept the band from playing Boston in 1975.

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WBZ NewsRadio 1030’s Joe Mathieu spoke with Davis