If you're looking for reputable textbooks and introductory reading, I would suggest going to one of the many open courseware sites at major universities (such as MIT, Berkeley or Yale). Look at the courses available for the subject you're interested in (psychology, in your case), find one that matches your interests, and check out the syllabus for that course. It should direct you towards good learning material for that subject.

Here, for instance, is a list of readings from the MIT intro psych class. Here's an MIT class specifically on autism.