This should more properly be called "Eight Doctors, One at a Time" because unlike the televised episodes with the titles "The N Doctors," the Eighth Doctor spends the book visiting one incarnation at a time in order. I advise anyone trying to start the BBC line of Who books to begin with "Vampire Science." "The Eight Doctors" is supposed to introduce the companion Sam, but she doesn't do anything related to the story until the very end where she jumps into the TARDIS (of which her casual acceptance is a bit strange to say the least). You get a much better picture of Sam's character in "Vampire Science."