A friend bought this as a gift for me 10+ years ago: The Personal MBA: Master the Art of Business by Josh Kaufman [0].

I've given it as a gift to other friends.

[0] https://www.amazon.com/Personal-MBA-Master-Art-Business/dp/B...

PersonalMBA really is a my go-to reference because it is very comprehensive and extremely accessible online. First 5 chapters tackle the strategy behind the '5 parts of every business'

1) Value Creation 2) Marketing 3) Sales 4) Value Delivery 5) Finance

The next 6 Chapters deal with the tactics involved in executing that strategy. 6) The human mind 7) Working With Yourself 8) Working With Others 9) Understanding Systems 10) Analyzing Systems 11) Improving Systems

Then If you REALLY wanted to dive deeper, you can read the 99 business books he built the personalmba from: https://personalmba.com/best-business-books/

Josh Kaufman created something great here.

I'm currently following the marketing section of this one and it's been really helpful to compensate for my huge gaps in knowledge

Glad this is posted here - rare for a single amazon product to have so many high views from people with so many backgrounds.