Several good books on science of baking.

"Cookwise" by Shirley O. Corriher
"On Food and Cooking" by Harold McGee (now in second edition great reference for a pros and foodie)
"Baking and Pastry" by CIA Culinary Institute of America professional text book explains whys of baking. soda + creme of tartar vs powder etc. How to get the golden brown color or not.

Three of my favorite cookbooks

"The Secrets of Baking" by Sherry Yard (laminate recipe is by far the best and very forgiving. level: beginning to pro)

"Tartine" by Elisabeth M. Prueitt and Chad Robertson level: beginning to pro
"Betty Crocker's Cooky Book" 1963 edition. It has old recipes I just love. level: beginning

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As for the texture, I saw Alton Brown's show really concise and informative.

If you are not sure or can't get that episode, the information came directly out of "Cookwise" (just don't depend on her recipes. She may know the science but her recipe is bit of hit or miss).

One thing missing in Cookwise or Alton Brown's show is a discussion on temperature of the dough. It has a big effect on the final product. Another big ?? is the baking temperature. I always keep two thermometer in the oven. And I sometimes adjust the temperature profile during baking to get what I want. Lower temp and longer makes the dough run and dry out. High temp for short time then reducing to finish makes the cookie thick.

Flour choice for home use in order of softest/no structural body to CHEWY (low gluten to highest gluten content).

cake flour
pastry flour
AP flour
bread flour

Baking is fairly exact science so pay attention to measuring out your ingredients.

If you are experimenting, change the type of sugar, flour, temperature profile while baking, adding milk or not ... When you do make changes to the recipe change only one or two items at a time.

Shortning gives it that cheap bakery good taste. I refuse to use it. And don't substitute butter with margerine or the other way around. Not the same at all !! Always use unsalted butter in baking.