100 pages of two pictures that seemingly are identical are presented on the same page, but subtle changes have been made between the pictures. It's up to you to find what has been altered. Variety of puzzle types and difficulty Can't find all the changes? Solutions to all the puzzles are provided in the back of the book. 100 interesting picture puzzles - each with a range of 9 to 14 differences to find. Each puzzle is designed to keep your vision sharp and help improve memory and focus Great adult gift for birthdays, holidays, and travel! Made to challenge your powers of observation and stimulate your ability to focus and concentrate. Amazon Customer 5.0 out of 5 stars Good book Good puzles of all levals of difficulty all are done in black and white print which makes it not always to do. hilary mcdonald 5.0 out of 5 stars Sharpens your observation Hours of fun , it sharpens your observation too . Diane williams 4.0 out of 5 stars Looks good Bought for stocking filler