I really like the book "The Genius Wisdom" by the genius of marketing and branding Jack Trout.
The book covers all topics needed for a successful business.
One of the chapters was of special interest for me. It is "Chapter 10. How Important Are Logos?"
It has a lot of interesting information on logo design, I want to list here my favorite quotes:
"No matter how cute, if it's tough to read, forget about it."
"Your brand-new symbol probably has no chance of standing alone without your name."
"The name is far more powerful than a symbol. A logo should be designed around the name."
I use recommendations from this book in my work and think that any designer should follow them.
I highly recommend you to read this book, it is easy to read and very useful.