I'm curious how close the research community is to general AI

Nobody knows, because we don't know how to do it yet. There could be a "big breakthrough" tomorrow that more or less finishes it out, or it could take 100 years, or - worst case - Penrose turns out to be right and it's not possible at all.

Also, are there useful books, courses or papers that go into general AI research?

Of course there are. See:

https://agi.mit.edu

https://agi.reddit.com

http://www.agi-society.org/

https://opencog.org/

https://www.amazon.com/Engineering-General-Intelligence-Part...

https://www.amazon.com/Engineering-General-Intelligence-Part...

https://www.amazon.com/Artificial-General-Intelligence-Cogni...

https://www.amazon.com/Universal-Artificial-Intelligence-Alg...

https://www.amazon.com/How-Create-Mind-Thought-Revealed/dp/0...

https://www.amazon.com/Intelligence-Understanding-Creation-I...

https://www.amazon.com/Society-Mind-Marvin-Minsky/dp/0671657...

https://www.amazon.com/Unified-Theories-Cognition-William-Le...

https://www.amazon.com/Master-Algorithm-Ultimate-Learning-Ma...

https://www.amazon.com/Singularity-Near-Humans-Transcend-Bio...

https://www.amazon.com/Emotion-Machine-Commonsense-Artificia...

https://www.amazon.com/Physical-Universe-Oxford-Cognitive-Ar...

See also, the work on various "Cognitive Architectures", including SOAR, ACT-R, CLARION, etc,

https://en.wikipedia.org/wiki/Cognitive_architecture

"Neuvoevolution"

https://en.wikipedia.org/wiki/Neuroevolution

and "Biologically Inspired Computing"

https://en.wikipedia.org/wiki/Biologically_inspired_computin...

You may enjoy The Master Algorithm: http://www.amazon.com/Master-Algorithm-Ultimate-Learning-Mac...

The author of this paper, Pedro Domingos[1], just wrote a book on machine learning titled The Master Algorithm[2]. In the book, he talks at length about the various elements that may serve as (part of) the basis for a "master algorithm" - a generalized learning algorithm capable of learning anything. Rule induction is one of the things he talks about in the book, so at least one expert seems to think this stuff is still relevant.

Of course, it might just be that this is his pet "thing" and for all I know he could be totally wrong, but it struck me as interesting enough to start doing some reading on. And hence this post.

[1]: https://homes.cs.washington.edu/~pedrod/

[2]: http://www.amazon.com/The-Master-Algorithm-Ultimate-Learning...