Reply #209: There aren't differing theories of evolution.

[laconicsax]

There are disagreements on the details, none of which affect the theory of evolution on the whole the same way the debate over the best method of putting a spacecraft in orbit doesn't affect the theory of gravity.

As for which book, I'd recommend Climbing Mount Improbable or Why Evolution is True. You might try using a public or school library--if you're a college student, your school should have at least a few of the books I recommended.