Spending at UK booksellers was down 1.5% year-on-year in October although this was an improvement on September when sales were down on 2009 by 3.2%.
Book sales in October dropped by £2.3m year-on-year, to £144.7m, according to Nielsen BookScan data. Volume sales were down 3.3% (562,000) to 16.7m, however the actual selling price was up 1.8% (15p) to £8.65.
Genres down year-on-year include sci-fi, which may be due to Terry Pratchett's Unseen Adademicals (Doubleday) being classed as sci-fi last year whereas this year's I Shall Wear Midnight (Doubleday Children's) is a children's Discworld novel.
Crime is also down year on year, due to Dan Brown's The Lost Symbol (Transworld) selling huge numbers in hardback last year.
Historical fiction is down year-on-year due to the success of Hilary Mantel's Booker-winning Wolf Hall (Fourth Estate) in 2009 and both children's fiction and children's annuals have too seen a slide year on year.
Genres seeing a rise in sales include the food and drink category, thanks to Jamie Oliver's Jamie's 30-minute Meals (Michael Joseph) and biography & memoirs with celebrities appearing to be bouncing back in 2010.
Meanwhile US book sales hit a 2010 low in September, with revenue falling 7.7% to $1.51bn.
Publishers Weekly, quoting US Census Bureau figures, said the decline followed a 6.5% drop in August.
Overall US book sales are down 2.6% to $12.31bn for the first nine months of the year.