The history of science is not restricted to the achievements of big scientists or big scientific institutions.Contributions can also be made by researchers with the necessary background, curiosity and enthusiasm.In the period 1973-1974 we were investigating practical applications of electron interferometry with a Siemens Elmiskop 101 electron microscope that had been carefully calibrated at the CNR-LAMEL laboratory in Bologna,where one of us(PGM)was based (J.Phys. E7729-32) These experiments followed earlier work at the Istituto di Fisica in 1972-73 in which the electron biprism was inserted in a Siemens Elmiskop IA and then used both for didactic(Am.J.Phys.41 639-644)and research experiments (J.Microscopie 18 103-108).We used the Elmiskop 101 for many experiments including,for instance,the observation of the electrostatic field associated with p-n junctions (J.Microscopie 21 11-20). During this period we learnt that Professors Angelo and Aurelio Bairati in the Institute of Anatomy at the University of Milan had bought an image intensifier that could be used with the Elmiskop 101.Out of curiosity,and also realizing the conceptual importance of interference experiments with single photons or electrons,we asked if we could attempt to perform an interference experiment with single electrons in the Milan laboratory.Our results formed the basis of the film "Electron interference"and were also published in 1976(Am.J.Phys.44 306-7). Following the publication of the paper by Tonomura and co-workers in 1989,which did not refer to our 1976 paper (although it did contain an incorrect reference to our film),the American Journal of Physics published a letter from Greyson Gilson of Submicron Structures Inc.The letter stated:"Tonomura et al.seem to believe that they were the first to perform a successful two-slit interference experiment using electrons and also that they were the first to observe the cumulative build-up of the resulting electron interference pattern.Although their demonstration is very admirable,reports of similar work have appeared in this Journal for about 30 years (see,for examples,Refs.2-7.)It seems inappropriate to permit the widespread misconception that such experiments have not been performed and perhaps cannot be performed to continue."(G Gilson 1989 Am.J.Phys.57 680).Three of the seven papers that Gilson refers to were from our group in Bologna. Single-electron interference at BolognaThe main subject of our 1976 paper and the 1989 paper from the Hitachi group are the same:the single-electron build-up of the interference pattern and the statistical aspect of the phenomena.Obviously the electron-detection system used by the Hitachi group in 1989 was more sophisticated than the one we used in 1974.However,the sentence on page 118 of the paper by Tonomura et al.,which states that in our film we "showed the electron arrival in each frame without recording the cumulative arrivals",is not correct:this can be seen by watching the film and looking at figure 1 of our 1976 paper(a version of which is shown here). Finally,it is also worth noting that the first double-slit experiment with single electrons was actually a by-product of research into the practical applications of electron interferometry.The history of science is not restricted to the achievements of big scientists or big scientific institutions. Contributions can also be made by researchers with the necessary background, curiosity and enthusiasm. In the period 1973-1974 we were investigating practical applications of electron interferometry with a Siemens Elmiskop 101 electron microscope that had been carefully calibrated at the CNR-LAMEL laboratory in Bologna, where one of us (PGM) was based (J. Phys. E7 729-32). These experiments followed earlier work at the Istituto di Fisica in 1972-73 in which the electron biprism was inserted in a Siemens Elmiskop IA and then used both for didactic (Am. J. Phys. 41 639-644) and research experiments (J. Microscopie 18 103-108). We used the Elmiskop 101 for many experiments including, for instance, the observation of the electrostatic field associated with p-n junctions (J. Microscopie 21 11-20). During this period we learnt that Professors Angelo and Aurelio Bairati in the Institute of Anatomy at the University of Milan had bought an image intensifier that could be used with the Elmiskop 101. Out of curiosity, and also realizing the conceptual importance of interference experiments with single photons or electrons, we asked if we could attempt to perform an interference experiment with single electrons in the Milan laboratory. Our results formed the basis of the film "Electron interference" and were also published in 1976 (Am. J. Phys. 44 306-7). Following the publication of the paper by Tonomura and co-workers in 1989, which did not refer to our 1976 paper (although it did contain an incorrect reference to our film), the American Journal of Physics published a letter from Greyson Gilson of Submicron Structures Inc. The letter stated: "Tonomura et al. seem to believe that they were the first to perform a successful two-slit interference experiment using electrons and also that they were the first to observe the cumulative build-up of the resulting electron interference pattern. Although their demonstration is very admirable, reports of similar work have appeared in this Journal for about 30 years (see, for examples, Refs. 2-7.) It seems inappropriate to permit the widespread misconception that such experiments have not been performed and perhaps cannot be performed to continue." (G Gilson 1989 Am. J. Phys. 57 680). Three of the seven papers that Gilson refers to were from our group in Bologna. Single-electron interference at BolognaThe main subject of our 1976 paper and the 1989 paper from the Hitachi group are the same: the single-electron build-up of the interference pattern and the statistical aspect of the phenomena. Obviously the electron-detection system used by the Hitachi group in 1989 was more sophisticated than the one we used in 1974. However, the sentence on page 118 of the paper by Tonomura et al., which states that in our film we "showed the electron arrival in each frame without recording the cumulative arrivals", is not correct: this can be seen by watching the film and looking at figure 1 of our 1976 paper (a version of which is shown here). Finally, it is also worth noting that the first double-slit experiment with single electrons was actually a by-product of research into the practical applications of electron interferometry