In his elaborately researched book Miroslav Tischler has documented the life and work of Eduard Slavoljub Penkala (1871–1922) as well as the history of the firm Edmund Mostar & Co. — the later Penkala works. Penkala was not only an important designer and inventor in the writing-instrument field but also the constructor and pilot of the first aircraft built in Croatia. Presumably it was he who invented the piston filler; in 1927 the Penkala works sold the patent of a fountain pen with differential piston to Günther Wagner, from which the well-known Pelikan fountain pens later emerged. Penkala also held patents for mechanical pencils, further writing instruments and improvements to the gramophone or to the material of gramophone records.
The large-format volume (about 24 x 33 cm) comprises around 152 pages with excellent photos of writing instruments, documents, ads and advertising. Content-wise it is divided into preface, history of Penkala and the Penkala works, writing instruments (filling pencil, mechanical twist pencil, fountain pen, safety pen, lever filler, push filler, bumper pen, eyedropper system, piston filler), factory in Lepoglava, other products of the Penkala factory, clips, nibs, art of advertising as well as chapters on other Croatian stationery makers — including Günther Wagner K.D. Pelikan factories in Zagreb — and other international makers. From the last chapter previously unknown piston fillers such as Juwel (Deutsche Füllhalterwerke GmbH, formerly Angloamer) or OWA (Peter Jungmann, Heidelberg/Dossenheim) can also be unambiguously assigned. In 1909 Penkala incidentally founded a Berlin branch in which writing instruments were also produced.