i did own a signed the simpsons poster for years and looked at it almost every day and at first sight i think the autograph in your book looks good to me but there are people who can draw and sign a matt groening easily so some info and proof from the seller would give you a better feeling. look at ebay.com and compare your groening with psa or beckett authenticated items from him...even than you see many different styles of drawings and autographs.