Open Source API for trading algorithms? best way the get in to it [ Algorithms Trading]? book? Examples? tutorial?

Hi all, Is there any Open Source API for trading algorithms? Also what is the best way the get in to it [ Algorithms Trading] if you do not work in the financial industry. book? Examples? tutorial?

----- May I ask you why you specifically need Open Source? You can find several APIs (even for demo accounts) out there; you can use them for free (at least i…