There are several ways in which the mathematical functions encountered in theo-
theoretical physics and applied mathematics may be classified. As research students in
the late nineteen forties and the early nineteen fifties we used to distinguish between
Johnke-Emde functions and non-Jahnke-Emde functions. This - admittedly some-
somewhat facetious - distinction came from the Tables of Functions with Formulae and
Curves by Eugen Jahnke and Fritz Emde, the second edition of which had been pub-
published by B. G. Teubner (Leipzig and Berlin) in 1933. The "Jahnke-Emde", as it
was affectionately called, was a fascinating and quite unusual book. The text was in
German and English. It contained tables and diagrams that facilitated computations
involving complex numbers and solving cubic equations. In those days, when slide
rules and tables of the so-called elementary transcendents (logarithms, trigonomet-
trigonometric and hyperbolic functions) were the main paraphernalia of numerical computing
and when hand-operated desk calculators were highly treasured rarities, the material
provided in the book was an immense help in numerical work. The practical mind of
Fritz Emde, the sole author of the second edition after Eugen Jahnke had died in 1921
iwelve years after the first edition had appeared, may be gathered from the fact that
the extensive listing of tables of the elementary transcendental functions provided
not only comprehensive characterizations of the contents of the tables but also stated
which of them were out of print and which were available, and if so, at what price!