This is the first of six pocket notebooks used by Charles P. Mott, a member of the office staff at Menlo Park, to record daily activities at the laboratory. The entries from these notebooks were used as the basis for more extensive entries recorded by Mott in Menlo Park Notebooks #53 and #117. This pocket notebook, which covers the period April-May 1880, begins about one month after Mott\'s first Menlo Park notebook. The front cover is labeled \"150\"" and is inscribed \""Notes taken by the way\"" and \""1st.\"" The back cover is inscribed \""1880.\"" The book contains approximately 40 unnumbered pages."