Michelle Obama demonstrated a fresh skill to the American people last week when she completed an impressive 142 swivels of a hula hoop on the South Lawn of the White House at a "healthy kids fair" to promote fitness and nutrition for children. She hitched up her studded belt over a blue cardigan, held out arms hung heavy with bangles and skilfully sashayed hips clad in figure-hugging black capri trousers.

Mrs Obama was again filling the role she gave herself during her husband's presidential bid of the nation's "Mom-in-chief". For her legions of fashion devotees, it was also further evidence of the style she has brought to events ranging from glitzy dinners to physical work-outs.

Almost a year after Barack Obama won that historic race, there have been numerous books about the election, the first African-American incumbents at the White House and a new era of American politics.

Now the First Lady is now the subject of a series of glossy books celebrating a closet that has made the transition from the campaign trail to Washington. Published this week by Hachette, Mrs O: The Face of Fashion Democracy is a tribute to the mix of designer brand with high street outfits that is earning her glowing acolades.