I'm a beginner of Esperanto and I like to read so I'm wondering what are some translations of English-language books both fiction and nonfiction?

You might wonder why I ask for translations and not native literature and that is because it's a lot easier for me to stay motivated if it's a story that I'm already familiar with. In time as I become more comfortable reading in Esperanto then I will shift to some native literature.

Things of interest to me: science in general, some philosophy, such as logic and ethics, mathematics, and anarchism. As for fiction I'm sure there are some stories that I like that are translated in Esperanto like Journey to the center of the earth, Alice's adventures in wonderland, and Sherlock Holmes stories but I don't know what the quality of these translations are as a beginner.

You could start by browsing Project Gutenberg's collection of literature in Esperanto in author order:
http://www.gutenberg.org/browse/languages/eo

You might follow that up with a visit to the catalogue of Universala Esperanto-Asocio (UEA)
http://katalogo.uea.org/ Under 'Aŭtora nomo' try searching for 'Verne'. If something looks interesting, you can sometimes find it at http://books.google.com

Thanks for your help.

I've uploaded several EO translations of B. Traven's novels here it has his two most famous novels (Mortula Ŝipo kaj La trezoro de la sierrao madre). I recommend starting with the short story, la aktoro kaj la reĝo