Is Thinking a conscious process?

There is a book on this that was recently a best seller, the title is "Fast and Slow Thinking" or something like that. The main idea is that the human brain has, sort of, two different things going on at the same time. For example, there are things our brain recognizes and classifies as a "known thing" (which happens automatically without conscious thought) and there are things the brain does not automatically recognize so you have to consciously think about what it is. Unfortunately, this automatic function can be wrong. Magicians take advantage of this all the time.

Your brain is aware of things that you are not. You do not normally think about how your butt feels against the chair or how your shirt collar feels against your neck or how your toes feel against your shoes but the nerve impulses for all these things (and many more) are constantly going to your brain. This makes perfect sense evolutionarily because, if you were conscious of all this stuff all the time, your brain would have very little time left over to notice: Oh, that looks like a lion that is sneaking up on me to have me for lunch. With this in mind, it is a very good thing for your conscious brain to disregard stuff that is normal so that it pays particular attention to anything that is abnormal.

Only part is conscious. Read the first two references. For a (perhaps extreme) view on whether you have control of it, read the third.

thinking CAN be conscious, like problem solving, planning, or memorizing, but MOST thought is unconscious processing of sensory information