Longer and more complex than the standard ST novel,
Strangers from the Sky is a novel within a novel; that is,
Strangers from the Sky is also the title of a work of purported non-fiction concerning the first contact of Vulcan and Earth. The reading of this text triggers suppressed memories in Kirk and leads to the narration of a framed time-travel narrative. And then there are also the points of view of other individuals who lived in the earlier era which the imaginary non-fiction work describes... The actual book is less confusing than my attempt to explain, although the first time I read it I got kind of lost.