Maps are an essential part of genealogical research. As you know, political boundaries change, country names change, counties and parishes change boundaries, towns merge or are annexed. All sorts of things change.
In order to be sure that you're looking in the right place for records, you need to consult a correct map for the time period in question.
This CD certainly makes life easy, and is an incredibly useful resource as it already has numerous maps of the counties listed, each from different time periods, and all scanned at really high-resolution so that you can zoom in and in to see the finest detail.
Maps covered on this CD:
Berkshire 1695, 1806, 1839, 1847, 1869, 1903
Hampshire 1695, 1839, 1849, 1885, 1889, 1927
Isle of Wight 1911, 1927 (earlier maps of Hampshire also include the Isle of Wight)
Wiltshire 1695, 1839, 1842, 1849, 1903, 1927