Alex Hirsch's The Book of Bill, the first Gravity Falls book for adult readers, proved immensely popular with fans when it hit store shelves last July. The illustrated novel (of sorts) debuted at No.

There’s a new Gravity Falls book on the way, and this time it’s all about everyone’s favorite evil and triangular demon, Bill Cipher. Creator, (and also the voice of Bill) Alex Hirsch, announced the ...