Complex sentence: From 1991 to 1997 all books (except the final one) involved the Seventh Doctor, played on television by Sylvester McCoy; in further books published between 1997 and 1999, the New Adventures series focused on the character Bernice Summerfield and the Doctor did not appear.
Split into simpler sentences: From 1991 to 1997 all the books except the final one involved the Seventh Doctor, who was portrayed on television by Sylvester McCoy. In further books published between 1997 and 1999, the New Adventures series focused on the character Bernice Summerfield and the Doctor did not appear.