The Subjunctivisor!
Does buscar require the subjunctive?
Buscar may require the subjunctive, depending on whether there is doubt:
Por ejemplo …
Busco un libro que sea interesante.
I am looking for an interesting book.It may not exist = doubt = subjunctive.
Busco el libro que estoy leyendo.
I am looking for the book I am reading.It definitely exists = no doubt = no subjunctive.