Conocer= to know people and places (or to be familiar with people or places) Saber= to know facts and information, and to know how to do something To sum it up: Use "conocer" for familiarity and "saber" for knowledge. Examples: 1. Conocemos a Susana= We know Susana. 2. Ella sabe la dirección de su amigo = She knows her friend's address. 3. Yo conozco a la madre de Susana= I know Susana's mother. 4. Ellos saben cocinar= They know how to cook. 5. El turista conoce la ciudad de Madrid= The tourist knows/ is familiar with the city of Madrid.

No "conocer" and "saber" are almost never interchanged. Because they mean the same thing in English, but not in Spanish. When you are talking about knowing someone you have to use "conocer", but if you are talking about knowing how to do something then you use "saber".