Mr. J. Burnett -
Few left, indeed. Remember when there were Heathkit and Lafayette Electronics retail stores? We're lucky there's still Radio Shack stores around.
About op amps. For my own part I confess that I've found it hard to get my mind around them, in the past 32 years that I've been working with IC's.
The basics of operating an op amp is portrayed as simple and straightforward. Nevertheless the more useful op amp configurations are non-obvious.
Whenever I've considered using an op amp in a project, I've had to search through all the circuits on every page of my Forrest Mims Notebooks, or my Linear Databook of IC's (3'' thick), or the Op Amp Cookbook by Walter Jung, or the Active Filter Cookbook by Don Lancaster. Or the book of circuits in my Radio Shack electronics lab with breadboard.