The reason is that mass-market books no surprise tend to sell in larger numbers than trade.

The books have acquired an international cult following and tend to sell out within weeks of publication.

Such books tended to be melodramatic works about social injustice.

But books, he noted, tend to be written with the wisdom of hindsight.

As it turns out, these books also tend to have high sales.

As @margegunderson points out, the books in pound shops tend to be pretty rubbish.

The most popular books tend to be either about politics or religion.

WordPress books tend to go out of date rather quickly.

In his own defense, he added, "My books tend to be bigger than theirs."

Her earlier books tended to get good reviews too but to sell poorly.