Book excerpt: In 1975, Steven Spielberg's Jaws transformed the Hollywood landscape, sparked a cultural phenomenon and took a huge bite out of the collective psyche, with the public always wondering what lurked just beneath the surface of the water. The first true summer blockbuster was a masterpiece of the thriller genre, following the terrifying ordeal of a beach community under attack by a monstrous great white shark. This LIFE special issue celebrates the 45th anniversary of this iconic film (which earned an Oscar nomination for Best Picture) with an in-depth look at Spielberg's revolutionary filmmaking and storytelling techniques, the chaotic making of the movie and its lasting legacy, and why, 45 years later, it's still scary.