By Jerry Spinelli (Harper Collins, 248 pages, $16.99, ages 10 and up)

10:15 a.m., Sept. 26. That's when geeky high schooler Will Tuppence's world turns on its head with news that a single proton has been caught in the act of dying. "Do you know what this means?" Will asks his two best friends, the coquettish Mi-Su and the reckless Anthony Bontempo, known by everyone as BT. "It means matter is mortal. Everything is going to go. Disappear. Vanish. Rock. Water. The planets. The stars. Everything." Although Will assures them, over their regular Saturday night game of Monopoly, that the end is trillions of years away, masterful teen author Jerry Spinelli speeds things up quite a bit. The Newbery Medal-winning Spinelli ("Maniac Magee," "Stargirl") understands teen angst better than most and throws plenty of it at poor Will. Jealousy -- are Mi-Su and BT an item? -- parental pressures, an unbearable little sister, an awful first kiss. But the book's terrifying denouement teaches Will that something far more precious than protons is at stake here. And in the lesson, he learns about love.