I find attempts to correlate doctor who continuity a bit pointless really. To be honest the TV show has contradicted itself from the start, add in comic strips, books, audio stories and you get a mass of conflicting material. This book attempts to give it some semblance of order but the best way to deal with doctor who continuity is not to worry about it! The book is well written and a lot of work has been done but it's not really necessary.