Die Zahl π – Altertum – Mittelalter – Neuzeit – Moderne — Studien-Edition in einem Band, 186 p. – E89 – Neuss 2022 – starting with Papyrus Rhind to proofs for irrationality and transcendency of Pi – with lots of constructions and disrete approximations, including outlook on computers and Pi – We may guess: this type of near to encyclopedical survey is RARE – and was in NEED to see the public light, because it really can advance studies!