The machine does not accept an approximate answer.
Software forgives. You run it, it breaks, you change a line, you run it again — the cost of being wrong is a few seconds. A lathe does not work that way. A wrong offset is a scrapped part, a broken tool, or a crash that takes the spindle with it. You are correct before you press cycle start, or you find out what being wrong costs.
Programs written for specific iron, kept with the documentation that makes them runnable by someone who was not there when they were written.
Turning programs for HAAS ST25 and Hwacheon, revision on revision. The rev numbers are not version-control hygiene — each one is a part that came off the machine and got measured.
Which tool in which station, what offset, what order. A program without its setup sheet is an instruction with the context removed — which is how the wrong tool ends up in the cut.
FANUC Series 0i-F, the full set — parameter, operator, maintenance. Kept, because at some point a machine throws an alarm that only the parameter manual explains.
A lathe simulator, to run the toolpath before the toolpath runs in steel. Find out what is wrong while being wrong is still cheap.
The rest of this atlas is software — things that exist because they were typed. This is the part that proves the thinking survives contact with a material that pushes back. It is also the oldest discipline represented, and the one that taught the rule every other page depends on: measure it, do not assume it.