What Can it Mean When You Say "I Know"?
If you've ever studied Spanish, or if you are taking it now and not getting enough clarity to tell the difference between saber and conocer, then you've probably already read or been told that they both mean to know and that saber is used when you refer to information or facts that one knows. The verb conocer, on the other hand, is used when one refers to knowing people or places one knows. All this is true, but by using the English verb to know when translating examples doesn't really unravel the problem, does it?
That is, if you see Conozco a Pedro (I know Peter) and Sé mucho de esta ciudad (I know a lot about this city), the examples don't show you the difference between how the verb to know is used in English, so the rules above about the two Spanish verbs may seem to ring hollow unless you quickly see the notion of familiarity in the first sentence and the notion of information in the second. This could get more confusing if you read sentences like Conozco la canción (I know the song), Sé la letra (I know the [lyrics of the] song) and Conozco la ciudad (I know the city).
Beginners can avoid confusion from day one by not translating conocer as to know but rather as some form of to be familiar with or to be acquainted with.
That's the secret for clearing confusion when English has one and Spanish has more than one verb: Avoid the translation of conocer as to know, learners will automatically not use it with the uses reserved for saber, and even use conocer properly when they use it with object other than people; for instance, when they do not mean knowing facts about a city but rather being familiar with it. Likewise, the example of the song, in which using saber means to be able to sing it or play it, whereas using conocer means remembering having heard it on the radio -- as in naming that tune in so many notes.
Remember only that when using conocer when expressing being familiar with people, you must use the personal a: Conozco a Pedro.
Two more observations about saber are in order. As a helping verb, followed by an infinitive, it answers to the English expression how to: how to do something -- como is not used: Sé nadar (I know how to swim). Also, when saber is followed by a, it has nothing to do with knowing, but actually means to taste like: Sabe a manzanas (It tastes like apples).
Finally, be careful in the preterite, where both of these verbs take on different meanings.