Cable TV mogul John Malone made a surprise offer last night to buy Barnes & Noble for $1 billion.

The billionaire CEO of Liberty Media — which owns the QVC and Starz cable networks, as well as stakes in Expedia and Sirius XM Radio — is looking to harness B&N’s fast-growing Nook e-reader device to further distribute his media content, industry insiders speculated.

The offer, which amounts to $17 a share, sent B&N shares soaring 24 percent, to $17.50 a share, above Malone’s offering price..

Malone’s offer comes as a half-hearted auction of New York-based B&N launched last summer appeared to grind to a halt this spring.

That’s partly because the bookseller’s heavy investments in the Nook e-reader appear to be paying off, capturing 25 percent of the digital-books market, according to B&N.

In the coming weeks, some investors expect B&N to report brisk growth in demand for the Nook, citing recent reports of ramped-up production in Asia.

Despite cash constraints as book sales at B&N stores continue their multiyear decline, CEO Len Riggio is funneling $150 million into developing the e-reader in a bid to compete with Amazon.com’s Kindle and Apple’s iPad.

Next week, B&N is expected to announce a new e-reader, the Wall Street Journal reported yesterday.