I would strongly recommend books that are research based studies of fish and aquatic environment type content. There is much to learn from such books and after I say a few words I'll list a few titles for you. A quick search on Amazon will reveal authors and pricing.
Magazines; You'll not rush for this one perhaps but Scientific American has always been a favorite with me. Fly fishing magazines have become an almost continuous Gear Reviews and marketing tool compared to the introduction of the original Fly Fisherman magazine in the mid 70's. Yes they always had ads from tackle companies but no where on the scale of today.
Books: Below are titles and links to the book and details about them.
'Trout' by Judith Stolz: (Editor) [ame="http://www.amazon.com/Trout-Wildlife-Judith-Stolz/dp/081171652X/ref=sr_1_fkmr0_1?ie=UTF8&qid=1294013043&sr=1-1-fkmr0"]Amazon.com: Trout (Wildlife Series) (9780811716529): Judith Stolz: Books@@AMEPARAM@@http://ecx.images-amazon.com/images/I/41K6F9J2RVL.@@AMEPARAM@@41K6F9J2RVL[/ame]
'What Fish See' by Colin Kageyama: [ame="http://www.amazon.com/What-Fish-See-Understanding-Designing/dp/1571881409/ref=sr_1_1?s=books&ie=UTF8&qid=1294013175&sr=1-1"]Amazon.com: What Fish See: Understanding Optics and Color Shifts for Designing Lures and Flies (9781571881403): Colin J. Kageyama: Books@@AMEPARAM@@http://ecx.images-amazon.com/images/I/51BYH3VN57L.@@AMEPARAM@@51BYH3VN57L[/ame]
Through The Fishes Eye by Clark & Sosin: [ame="http://www.amazon.com/Through-Fishs-Eye-Gamefish-Behavior/dp/B000K5Q6T4/ref=sr_1_1?s=books&ie=UTF8&qid=1294013289&sr=1-1"]Amazon.com: Through the Fish's Eye: An Angler's Guide to Gamefish Behavior: Mark & Clark, John Sosin, B/W Illus: Books@@AMEPARAM@@http://ecx.images-amazon.com/images/I/510KUFxmJML.@@AMEPARAM@@510KUFxmJML[/ame]
These are good foundation reading for those who wish to not only understand trout but as an aid in planning approach, presentation, and choice of flies and colors based on water conditions. I have found little to be gained by reading stories about someones success and seeing the pictures of far away places. However I have found that by tailoring my education to focus on my hobby I have became a good enough fisherman that the articles fail to impress me any longer. And I don't miss the advertisements a bit.
I hope you find that this approach makes sense form the prospective of a fisherman,
Ard