Otaku is often mistakenly defined as the Japanese word for "nerd." That's not quite right, Patrick Galbraith explains in the introduction to his new book, Otaku Spaces. In fact, otaku involves "socially unacceptable forms of play and consumption," which means it has less to do with being the Japanese equivalent of a Trekker and more to do with good old-fashioned hoarding. Galbraith interviews Japanese otaku about their obsessions—they surround themselves with manga, with anime, with statuettes and costumes, and they don't have time for friends because they're too immersed in fantasy to pay attention to something as dull as meatspace.

The book is certainly a beautiful object. Galbraith's interviews are accompanied by Androniki Christodoulou's full-color, full-page photographs of otaku in their homes. A young man clowns around with his extensive collection of fast-food mascot toys (including at least two Hamburglar iterations). A young woman seems to sleep on an angry sea of thousands of DVD and video game cases. A guy crouches by his bookshelves, trying to read two comic books at once. A few men pose with body-sized pillows that have ostensibly sexy cartoon women printed on them.

"It is very embarrassing to talk about it," one of the men tells Galbraith about his favorite video game, "because it directly shows my inclinations." That's a great explanation of otaku, in which the interior life becomes exterior. Women who can't form relationships in real life explain why they enjoy collecting thousands of copies of homoerotic "boys' love" manga. "The appeal of BL is that it is a love story between individuals, not between sexes," one woman says, and you can practically feel her yearning to be loved as an individual. Thirty-five-year-old men surround themselves with 3-D representations of "perfect" hydrocephalic beauties and wonder why they remain unloved.

There's nothing explicit about this book, but the scent of sex is everywhere. There's such an intimate air to Christodoulou's photographs that you have to imagine what the subjects are hiding. (In the introduction, Galbraith mentions that one of Japan's few serial murderers was famously outed as an otaku.) But the interviews appeal, in the end, to our commonality: A few of the subjects gently point out that if people are honest with themselves, everyone is a little bit otaku about something.