The Home Orchard, published by University of California’s Agriculture and Natural Resources is a very accessible source of information and it absolutely must reading for anyone who wishes to be involved in growing food on trees. You can find their catalog with this book and many others at their site, here.
Sylvia Thompson’s The Kitchen Garden discusses some of these plants, but it’s just an inclusion in a general gardening text.
The Grape Grower: A Guide to Organic Viticulture by Lon Rombough is a beautifully illustrated and succinct guide to all things relating to grapes – not only wine, but also for eating.
Online sources include, but are not limited to (!):
From UC Davis:
Fruits and Nuts Research Center
And the appropriately named The California Backyard Orchard, also from UC Davis.
The Home Orchard Society (not our climate, but …)
California Rare Fruit Growers – I am a member and my Propagation class and my Home Orchard class will attend their meetings (next West LA meeting is on persimmons on November 8th), their breadth of knowledge and commitment to growing tree crops is astounding! I heartily recommend them.
Some general information from the Commonwealth of Virginia’s Cooperative Extension.
A commercial site with a lot of really good reference material:
Dave Wilson Nursery
And my favorite place to buy fruit trees, a very helpful and knowledgeable staff:
Trees Of Antiquity