Since you are a designer, what do you think the top design books for non-designers are? I'm primarily concerned with understanding the basics and language to better communicate with others rather than be the primary designer.
- Proximity
- Alignment
- Repetition
- Contrast
The book also provides a basic introduction to understanding and using type. The type section is not as strong as the first section of the book that covers design principles, but still useful.
I'll repeat that this is an absolute beginner's book for non-designers. There are many topics it doesn't cover that you might find in a beginner's book on Graphic Design. However, it provides simple practical advice you can put to use immediately in documents. That's why I think it's useful for non-designers. Since it is a well-known and popular title, you should be able to find it in your local library.
(Note: my comments above refer to the first edition of the book published in 1994, but there have been subsequent editions which will have updated content.)
This is a book that gives you a collection of techniques. Without the knowledge of why you should be using these techniques, you'll end up with weird designs that feel wrong intuitively but are correct technique-wise.
Based on your question I would go for the first 2 books: they are useful even for word processing and powerpoint slide-making