Social Sciences. In short, a two-mode is a hybrid vehicle that can operate in two distinct ways (modes). The first mode works much like a regular full hybrid. It is the second mode that makes the difference--where the hybrid system can adjust varying amounts of engine and motor function to meet very specific vehicle/task/traffic requirements.
Twain's first book, The Innocents Abroad, was published in 1869, The Adventures of Tom Sawyer in 1876, and The Adventures of Huckleberry Finn in 1885. He wrote 28 books and numerous short stories, letters and sketches. Mark Twain passed away on April 21, 1910, but has a following still today.
There are 17 primary works and 17 total works in the Enderverse: Publication Order Series. This series listing gives the Ender books in publication order. For the books in chronological order, see The Ender Quintet (which will also give more complete information about the series) and The Shadow Series. For other short stories of the Ender's universe, see Ender's Saga short stories.