Percy Bysshe Shelley 
The Necessity of Atheism [EPUB ebook] 

Just expressing an atheist opinion out loud was enough to set the wheels of British justice in motion in the 19th century. But Shelley went beyond that, arguing that atheism was a necessary position — the only one that could be reasonably held.
The poet Percy Bysshe Shelley was never one to hold back an opinion — and despite the laws against blasphemy, this included his opinion that God was pretend. While an Oxford student in 1811, Shelley wrote a strongly worded and well-reasoned pamphlet titled “The Necessity of Atheism, ” printed up a few hundred copies, and quietly scattered them around the Oxford grounds.
Shelley examined three types of evidence — human senses, human reason, and the testimony of others — dismantling each in turn as a valid foundation for belief. Having done so in under a thousand words, he concluded that atheism wasn’t just sound and reasonable, but the only real choice left standing.