Non Fiction: Multiple Bizarre or Scientific topics like Handwriting and Fingerprint Analysis or Historical Hoaxes and Discoveries. Read around 2007-2009.

[K the Vampire Slayer]

The book covered a variety of topics, the ones of which I remember most clearly being: a section on what your handwriting says about you, like the size and curve and spacing of the letters and what it means personality wise; a section on fingerprint analysis and possibly true crime; a section on the fairy photos that fooled Arthur Conan Doyle? and a section on hidden layers of paint beneath famous works of art like the Mona Lisa.
I read this book around 2007-2009, but I suspect it was published in the 90s or very early 2000s. It was large and I believe hardcover like one of those really tall/wide and thick books with a dark coloured cover and possibly a person with their mouth open on the front, but I'm not 100% sure about that fact. Edit: There were also pictures on most of the pages alongside the text. Edit 2: Pictures as in the occasional photos like in articles, not comics or illustrations.

[Rosa]

The Mammoth Encyclopedia of the Unsolved?

[Panda2778]

You might want to check This list of books about HOAXES

Specifically The Big Book of Hoaxes
Or 100 Hoaxes & Mistakes That Fooled Science