MurderByDeath
I'm accumulating quite a number of gardening books and if I'm not careful, someone is going to start thinking I know what I'm doing when I'm outside digging in the dirt. When MT and I started building our garden/back yard (there's no grass - just plants everywhere) we started from scratch and chemical free.
One of the first things I learned was to plant basil and marigolds with your tomatoes to control nematodes and aphids. I don't know about the nematodes, but do you know, our tomatoes never have aphids. My strawberries, planted in another section of the garden were covered in them this year, but not the tomatoes.
So I'm all about learning more about companion planting. Carrots Love Tomatoes is a pretty good reference for just that. The author provides a comprehensive list of plants divided into sections (vegetables, herbs, wild plants, fruit trees, etc.) and lists plants that will not only make beneficial companions but also plants to avoid pairing together if you want to avoid the botanical equivalent of the Capulets and the Montagues.
The back of the book includes suggested garden plans that take full advantage of companion planting and there are plans for all size gardens, including window boxes, balconies and children's gardens. I especially liked that he had a suggested garden layout for those that have to take physiological restrictions into account. He even includes a plan for a "spirit garden" which is not a garden to attract paranormal visitors, but rather a garden of plants used to make the spirits that haunt your bar drinks.
A source list at the back will be handy for those that live in the USA.