A historical review of electronic monitoring of insect feeding is presented, with special emphasis on the role of D. L. McLean and M. G. Kinsey in the invention and early development of the AC monitor. In addition, all publications written from 1964 through 1990 on the topic of homopteran probing behavior are summarized in Table 1, which lists in chronological order the year, type of monitor used, species recorded, brief results, types of behavioral correlations if any, and citation. Finally, issues pertinent to modern monitoring are presented, such as challenges in recording and analyzing data, (e.g., analogue-to-digital analysis of waveform measurements and new monitor designs), and challenges in interpreting data and drawing conclusions, (e.g., variation in and clear definitions of terminology, and different monitors and their waveforms).