“Dickens and Prince: A Particular Kind of Genius,” by Nick Hornby (Riverhead Books) Nick Hornby has been writing about pop culture since the 1990s, most famously his obsessive love of soccer in 1992’s “Fever Pitch” and of music in “High Fidelity,” three years later. Now he has yoked together two more objects of his intense fandom, Charles Dickens and Prince, to explore the similarities between creative geniuses separated by an ocean and nearly 150 years. On the face of it, they are an odd couple — a white 19th century British writer and a Black 20th and 21st century American musician.