The Ipcress File

And now I will unclasp a secret book, And to your quick-conceiving discontents, I’ll read you matter deep and dangerous.

Henry IV

Though it must be said that every species of birds has a manner peculiar to itself, yet there is somewhat in most genera at least that at first sight discriminates them, and enables a judicious observer to pronounce upon them with some certainty.

Gilbert White, 1778