This article presents a discussion about lifelogging and its applications. The author provides a brief history of lifelogging tracing back to 1945, when Vannevar Bush, a prominent American scientist, wrote an essay for The Atlantic Monthly called "As We May Think." Scientists deal with an increasingly unmanageable trove of data and other information, Mr. Bush wrote, but technology could help. Mr. Bush imagined scientists wearing little cameras on their heads to record lab work. He conjured an image of a desklike machine that could store thousands of pages a day in microfilm. He called his device a memory extender, or "memex"--a term that some researchers use today to describe their own suite of lifelogging tools. Here, the author not only presents several lifelogging projects but also views from several people regarding lifelogging.