Best known for its name-your-own-price plane tickets and pitchman William Shatner, Priceline Group Inc. is a quiet giant in the world of travel. Its $65 billion collection of travel websites, including, and its namesake, is worth more than its three biggest rivals combined. As Priceline closes out a decade of quadruple-digit growth, its new chief executive, Darren Huston , must find ways to keep the company's profit engine chugging. Most of that growth will come not from but from overseas units like Amsterdam-based, which Mr. Huston joined in 2011. Non-domestic business already accounts for more than 90% of the company's operating profit as online travel booking takes hold abroad. Mr. Huston's biggest challenge may simply be avoiding the law of large numbers—after growth spurts like the company's 41% revenue surge in 2011, it's hard to anticipate where the next big increases will emerge. Get the full story at The Wall Street Journal