The day after his mother's death in October 1977, the influential philosopher Roland Barthes began a diary of mourning. Taking notes on index cards as was his habit, he reflected on a new solitude, on the ebb and flow of sadness, and on modern society's dismissal of grief. These 330 cards, published here for the first time, prove a skeleton key to the themes he tackled throughout his work.

Embarrassed and almost guilty because sometimes I feel that my mourning is merely a susceptibility to emotion. But all my life haven’t I been just that: moved?

Struck by the abstract nature of absence; yet it’s so painful, lacerating. Which allows me to understand abstraction somewhat better: it is absence and pain, the pain of absence—perhaps therefore love?

—How strange: her voice, which I knew so well, and which is said to be the very texture of memory (“the dear inflection…”), I no longer hear. Like a localized deafness…

—”Never again, never again!” —And yet there’s a contradiction: “never again” isn’t eternal, since you yourself will die one day. “Never again” is the expression of an immortal. (Images courtesy Michel Salzedo.)

Barthes, like me, prefers blue pens.

I was fortunate enough to see—and now share with you—a handful of these diaries from 1977 in their original, hand-written form. (A collection of more than three hundred entries, entitled “Mourning Diary,” will be published by Hill and Wang next month.)