Goliath picks up where Behemoth let off, after a spot of bother and a revolution in Constantinople, and takes the Leviathan to Tunguska, Siberia, where Nikola Tesla is secretly investigating the progress of his death ray, which may end the war -- or life as we know it. Goliath hurdles on from there in the classic Westerfeld style, a cracking adventure story that revolves around science and engineering in equal measures with love, jealousy and honor. Soon, Aleks and Dylan are embroiled in the machinations of William Randolph Hearst and his feud with Joseph Pulitzer, Pancho Villa and his cinematographic civil war, and an impossible romance.
Westerfeld's best trick is to mix adventure and fact, and he is as adept at working history into his stories as he is biology (see his brilliant Peeps for a more biological tale), and the Leviathan trilogy is full of great, sneaky discourses on engineering, history, science, and war.
Even better, the Leviathan books are ably illustrated in vintage style by Keith Thompson, recalling the illustrated adventures of the Victorian and Edwardian eras -- the chimerical, Dr Moreauvian creations of Westerfeld's imagination are particularly suited to this kind of drawing, as, of course, are the cross-hatched mechaniks of the Clankers.