since we're in the careers subform then this is perhaps worth sharing:
You have 80,000 hours in your career.
Make the right career choices, and you can help solve the world’s most pressing problems, as well as have a more rewarding, interesting life.
https://80000hours.org
(some of the philosophy behind the above isn't exactly everyone's cup of tea, some of my friends are very much into it, I think it certainly gives you some good points to think about)
here are some free education sites (though some courses/sites have subscription models for certificates, nanodegrees etc..)
these two are a bit older than the rest and are providing free access to full fat university courses, not selling certificates:
https://ocw.mit.edu/index.htm (some of the featured modules on the MIT site have rather sparse content, just a few notes etc.. others have video lectures, problem sets etc..)
https://see.stanford.edu
you can get certificates from these sites, some courses are a bit watered down, still useful resources
https://online.stanford.edu
https://www.edx.org
https://eu.udacity.com (this one offers the nanodegrees, some of the content is developed in partnership with some big companies and they also offer a careers service)
https://www.coursera.org/
you can also find online content (lecture slides and notes, videos etc..) for certain topics/modules at various universities - CMU has entire modules available covering some subjects I was interested in for example.
I guess book recommendations can be a bit subject dependent, in the case of technical areas it can often be the case that if you search online you can find the book available for free (as in officially available for free from the author's website - though IMHO if you're going to actually make use of it after having an initial read/browse you ought to pay for a copy)
I'm not really too keen on books that sell you on some dream of retiring early, becoming rich etc... there is a lot of dross in this area (though I haven't read the suggestion in the OP so I'm certainly not going to criticise it specifically - there can always be exceptions here). The other thing I can't stand is NLP stuff, this creeps into management/leadership training courses that various companies pay $$$$ for, it is also widely believed/followed by various sales people. The problem is that it is basically pseudoscience, people might well swear by it it doesn't mean that the various techniques actually work in the they are claimed to and/or explanations for them are correct.
This book is worth a read:
https://www.amazon.co.uk/Black-Swan-Impact-Highly-Improbable/dp/0141034599 (it is a bit overhyped, the author is rather arrogant and seems to have completely misunderstood statisticians/modern statistics, it is still a good book though)
This should be compulsory reading for anyone working in the city - first published in 1841 and still relevant today:
https://www.amazon.co.uk/Extraordinary-Popular-Delusions-Madness-Illustrated-ebook/dp/B003I84MBO
this is great for networking:
meetup.com
for improving public speaking:
https://www.toastmasters.org
(though personally I've had fun with acting and improv classes)
