If you can find a copy, Stephen Edward Poe's A Vision of the Future-- Star Trek: Voyager
gives a lot of information on the birth and development of the series, including the introduction of Seven of Nine. There are lot of backstage anecdotes, though the book tends to jump around a lot on events rather than a sequential chronology. It does not cover the entire run of the series.
Poe had also written the granddaddy of Star Trek reference books, The Making of Star Trek
under the name Steven E. Whitfield.