The national tourist office, Secretaría de Estado de Turismo (Ministry of Tourism, Oficinas Gubernmentales, Bloque D, Av. Mexico, 30 de Marzo, tel. 809/221-4660, www.godominicanrepublic.com ), is an administrative office where you will most likely need an appointment to talk to anyone.
Specific tourist offices (oficinas de turismo) for each region in the book are in that destination’s chapter. Go to those offices if you want information regarding the region you are visiting. They may or may not be of any help. Sometimes they just have brochures to hand you, other times they are very chatty and have a wealth of information. Always cross-reference material that they give you with other information you get elsewhere.