Once again the Fifty Shades trilogy dominates the top ten. All the reviews I've read have been very critical of the quality of the books, and I'm guessing that their success is based mainly on hype (for a fuller rant see my comments on the UK Bestsellers list). For fans of the Obamas there's a couple of books creeping into the top ten, with Michelle seeming to go from strength to strength. There's also the standard appearances from The Hunger Games trilogy and the Game of Thrones series, with Cheryl Najafi's debut on throwing truly remarkable parties at least offering a little variety.

The top ten bestselling books in May, according to Amazon US:

1
Fifty Shades of Grey by E L James book cover
Fifty Shades of Grey
E L James
$9.57 from Amazon
2
Fifty Shades Darker by E L James book cover
Fifty Shades Darker
E L James
$9.57 from Amazon
3
Fifty Shades Freed by E L James book cover
Fifty Shades Freed
E L James
$9.57 from Amazon
4
Fifty Shades Trilogy by E L James book cover
Fifty Shades Trilogy
E L James
$28.71 from Amazon
5
You're So Invited by Cheryl Najafi book cover
You're So Invited
Cheryl Najafi
$19.49 from Amazon
6
A Song of Fire and Ice by George R. R. Martin book cover
A Song of Ice and Fire, 1-4
George R. R. Martin 
$20.50 from Amazon
7
Mockingjayt by Suxanne Collins book cover
Mockingjay
Suzanne Collins
$9.80 from Amazon
8
The Hunger Games by Suzanne Collins book cover
The Hunger Games
Suzanne Collins
$5.01 from Amazon
9
The Amateur by Edward Klein book cover
The Amateur
Edward Klein
$16.77 from Amazon
10
American Grown by Michelle Obama book cover
American Grown
Michelle Obama
$16.00 from Amazon
Prices correct on 31/05/2012