Galaxies are known to have existed, even 13 billion years or so ago. However, no one has witnessed them in the very first phase of their assembly. I have been working on a survey of such protogalaxy candidates, using large telescopes around the world. We are also developing a next-generation, wide- field camera for the Subaru Telescope in order that we can expand our survey. This will provide us with crucial signposts for the forthcoming era of the 30-meter class telescope.