When I was invited to write a short editorial describing the social component of Rett syndrome, I was both delighted to comply and uncertain about what would actually prove helpful to the readership. I assume most readers will be familiar with the general contours of the disorder: a period of apparently normal early development, followed by a gradual loss of acquired language and manual skills, some autistic features, seizures. But what is a child with Rett really like-how do these terse descriptive terms come to life in a real child? I decided to look back at a journal I began keeping when my daughter Chelsea was born. I addressed her future self in short daily entries, writing about her unfolding personality, looking forward to the day I could give her the journal and help her understand herself. This is as unbiased a view as I can give you of a child with Rett, since these notations (the earliest, at least) preceded any suspicion in my mind that something might be wrong. But a sense of puzzlement began to creep into the journal as early as six months, a full year and a half before the diagnosis was made. Here are some excerpts from the journal.