"Experiences certainly exist in time and, at the very least, may exist in space, but in addition any experience has a dimension which no object can have: it is either mine or not mine. And once we recognise this subjective dimension we have at our disposal something which could provide an answer to the problem of the individuation of disembodied minds."
The problem of identity is the problem of sameness through change: What is it that makes this chair the same as the one I sat in yesterday? Things get more interesting (or at least more complicated) when we consider persons: are the identity criteria for persons the same as for objects? In The Identity of the Self, Geoffrey Madell seeks to distinguish personal identity from general (or "impersonal") identity.
The book's structure is a bit hard to follow. Madell deals with three views on the issue, and arguments for and against each are woven together throughout the book. But with few exceptions, these arguments return to this point: The first-person point of view cannot be reduced to a third-person description. In other words, no third-person description of a particular individual can identify that individual as me without making use of the first-person. Madell presents this argument in a variety of ways, as well as presenting arguments for and against alternate views and drawing out some of the implications of the various positions (most notably in the ethics of personal responsibility). Discussions are heavy on thought-experiments, as is usually the case in discussions on this topic, and they can be brain-twisting at times. Still, even if Madell doesn't convince you to accept his view, the book should give you plenty to think about.
I like Madell's approach a lot (focusing on evidence from the first-person perspective), but his arguments were a bit thin. Most of the arguments rely on some highly controversial premise that he does no defend, such as that conceivability is a guide to possibility.