Macroscope

Probably the most significant of Piers Anthony's SF (he did mostly fantasy). The Macroscope floats in orbit; it's like a super Hubble Space Telescope, only that it doesn't use light, but particles called 'macrons', which allow the device to act as a telescope with no distortion, basically arbitrary resolution. Better even, it can see through matter (unlike light), can be focused on anything at any distance, and the information is transmitted instantaneously. The ultimate snooping device, that would give the NSA and its ilk everywhere instant hard-ons. Needless to say, that's what the device is being used for—plus a fig-leaf of science, to keep things respectable. Since macrons can be artificially generated, they can also be used for instant communication. And it looks like someone's communicating all right! There's a powerful macron signal pervading space that carries information, which, when deciphered by a sufficiently advanced intelligence results in driving them insane. Makes you want to stay dumb! Why it's on the list: This is an underestimated classic, dealing with the power of information and knowledge, and what they can do to the minds receiving them. It constructs an intriguing universe, based on a simple premise (that something like a macroscope can exist), and weaves an engaging and thrilling story around it. It's packed with ideas and driven by a small cast of believable and well-drawn characters. Hugo nominated in 1970. Read if you like: Space stories. Imaginative SF. A dash of romance. Reading just for fun.