I already have OpAmps for everyone but like many electronics texts, it describes what they are,how they work, what they do, and how to use them as components in circuits(monolithic op-amp ICs) but doesn't go in depth about the internals of an individual op-amp and how to actually design an op-amp oneself! That's what I'm looking for: A book that describes in detail the op-amp microelectronic circuit design down to the transistor level! In particular because I'm seeking to design one and first test it with discrete transistors.
There are several books that deal with the design of op amps.
A notable classic is
P. R. Gray, P. J. Hurst, S. H. Lewis, R. G. Meyer, Analysis and Design of Analog Integrated Circuits. 5th ed., Wiley, 2009 (Amazon link).
Another one I like, quite recent, is
S. Franco, Analog Circuit Design: Discrete & Integrated, McGraw-Hill Education, 2014 (Amazon link).