This Booklet has been written and compiled for the use of any student or layman who seeks concise and clear information on the history of Influenza. Brief and salient facts are set forth relating to "Flu" epidemics and pandemics: other collateral features have also been discussed, connected with or bearing upon this subject. EXPLANATION OF MEDICAL WORDS: Infection. The entrance into the system or body of living disease producing germs, such as by (a) Droplet infection; bacteria infected minute particles or droplets, ejected by sneezing, coughing, spitting and talking. (b) Aerial dust particles coated with bacteria. (c) Mixed, more than one bacterium or organism present in the system, they may enter together or one precede the other. Contagious. A disease acquired from a direct contact with the sick. Contagion. The spreading of a disease by direct or indirect contact.(a) Direct contagion. (b) Indirect contagion or mediate, as by a "carrier, " who is apparently in good health, but nevertheless carries disease and can convey it to other non-immune persons. (c) By means of Fomites (hereafter defined). Contagium. The virus or poison which transmits disease, such as the vaccine used in anti-smallpox vaccination, which in former years was obtained from the vacca or cow, now the calf is the source of supply. Fomites. Any non-animate agents or substances that transmit contagion such as blankets, towels, handkerchiefs, or any articles which have been contaminated by the secretions or excretions of the sick. Endemic. A disease which is permanently present in a people or district, it may become epidemic. Epidemic. A rapidly and widely spreading disease attacking many people. Pandemic. A wide and rapidly spreading Epidemic affecting many people and all countries. Sporadic. A disease occurring here and there, not attacking many people, not widely spread nor epidemic. Incubation. The period between the implanting or acquiring of a communicable disease and its development; and visible by external signs or other recognisable manifestations.