Another string of apps is causing trouble in the Android Market. Dozens of commercial book collections, including the entire Harry Potter series, have been posted to the official Android app store by a developer named UKER, attracting thousands of illegal downloads. UKER’s apps include full e-book text, and despite poor quality and iffy navigation, the free book downloads have gained in popularity. Titles include The Vampire Diaries, as well as 15 novels by Patricia Cornwell and a handful of Stephen King titles.

UKER’s apps have been removed by Google, but were promptly reactivated, according to a paidContent report. The illegal publisher’s app brings attention to Google’s bigger issue of dealing with determined app makers looking to exploit the Android Market. And for a developer like UKER, Google will have to take extra precautions in dealing with a potential competitor.

Google wants to be your personal media hub

Google has its own publishing arm, selling books for direct download through the Android Market. Not only is Google running a marketplace, but it’s leveraging its Android app hub to promote its own personal media services. Google’s grown the Android Market to include books, movies and music in recent months, looking to compete with Apple’s iTunes portal for digital media.

But even Apple finds it tough to balance its own publishing goals with the industry as a whole. Last week a group of Chinese writers brought a lawsuit against Apple for making their titles available through its stores without permission. It’s been an arduous journey for the publishing industry heading into the mobile world, fighting piracy issues similar to those the music and film industry have faced for several years.

TIME’s digital publishing promo

However, not everyone is having a negative experience with digital publishing. TIME, Inc. hopes to demonstrate its partnership potential with mobile platforms by giving away free downloads of all its titles at CES this year. With cross-device access, TIME’s promotion brought free access through an all-in-one subscription for Android smartphones and tablets, including the Kindle Fire. The publisher already has a longer-standing deal with NOOK, offering a free B&N tablet with a year-subscription for People magazine.