 In the Zone received mixed to positive reviews from music critics , who complimented its mix of different styles and Spears 's songwriting , but criticized her vocals for being distant and processed . Commercially , In the Zone became an international success , debuting atop of the charts in France and the United States , and peaking inside the top ten in fifteen countries . In the United States , she became the first female artist to have four consecutive number @-@ one albums . In the Zone went on to become the eighth best selling album of 2003 . 
