E-books, which according to PricewaterhouseCoopers represent a quarter to a third of consumer book sales in the United States and Britain, have largely failed to catch on outside English-language markets.

The reasons for this failure are complicated, rooted in cultural resistance from readers and economic policies that protect traditional publishers. Rules in countries like Germany and France prohibit the kind of deep discounts on digital books relative to print that have lifted e-book sales in English-language markets. But another, less publicized factor is taxation, which in the case of e-books is all over the map.

This month, the International Publishers Association released a survey of how digital and printed books are taxed in 79 countries, showing that e-books are on average taxed twice as highly as printed books, 12.25 percent to 5.75 percent. In many European countries, including Sweden, Ireland and Hungary, the value-added tax on a printed book is negligible or waived, while the same book’s digital version is taxed at more than 20 percent.