If our civilization as it is survives and does not collapse, then this "manual" is unnecessary.
It is only useful if our civilization has clearly failed.
Maybe sanitation was a huge mistake. Maybe antibiotics were a huge mistake. Maybe the remnants of humanity that survive the apocalypse will look back on a humanity all but wiped out by superbugs of their own making.
Maybe agriculture was a huge mistake. Maybe the march towards monocultures is inevitable, and the remnants of humanity that survive the apocalypse will look back on a humanity all but wiped out by blights or the total depletion of fertile topsoil.
For anything that we wish to impart to these remnants, there's a scenario where that is why we failed, because we must assume that we did fail to justify the attempt at the manual at all.