As with the majority of Indo-European languages, most Slavic languages, notably Russian and Polish (the latter of which will be used as an example here), have sets of prefixes one may add to verbs to alter their meaning in useful ways. English demonstrates this phenomenon, although much less consistently and with less organization: You can "un" many verbs, giving birth to "undo," "unerase," etc, however, as any native speaker will tell you, there are few to no clearly defined rules to explain which prefixes go where. What rules govern where to place "anti" and where "con?" Formal grammars of English include lengthy explanations of these rules, but to the non-linguist (unlinguist?), it is a mystifying subject and we often simply memorize the modified verbs instead of the possible prefixes.

Slavic languages, on the other hand, have none of these ambiguities and their verbal prefix usage is nice and regular. It is perfectly acceptable to memorize root verbs and all the prefixes and then create the needed verbs as needed and as applicable. All the available prefixes are listed here in Polish (and as a general rule these prefixes occur in all Slavic languages with the expected irregulaties and changes in spelling and pronunciation) with their meaning(s) and, where possible, an example using the verb pisac', to write.

Prefix       Meaning                       Example
------       -------                       -------           
do-          to, toward                    dopisac'    to add in writing    
na-          on, upon, in, completing      napisac'    to finish writing
nad-         above, near                   nadpisac'   to write a heading
o-, ob(e)-   of, about, around             opisac'     to describe
o-, od(e)-   away, from, back, off         odpisac'    to answer in writing, to copy
po-          after, doing for a time       popisac'    to write a bit
pod-         under, below, up to, toward   podpisac'   to sign
prze(d)-     in front of, before           przepisac'  to copy
przy(d)-     through, across, over         
przy-        at, near, close to, by        przypisac'  to add in the margin, to attribute
roz(e)-      dis-, un-, getting bigger     rozpisac'   to write out, to copy from music
s- or s'-    with, down                    spisac'     to draw a list
u-           off, on                       
w(e)-        in                            wpisac'     to inscribe
ws-          up
wy-          out                           wypisac'    to copy an excerpt, to subscribe
wz(e)-       up
z(e)-        with, together, removing      
za-          behind, completing            zapisac'    to write down, to bequeath

Of course, as with any language, there are exceptions and cultural nuances that one cannot pick up through grammar books. The meanings of each prefix often encompass a greater concept that alters the verb in strange ways; note that spisac', which means, literally, "down write" or "with write" means to draw up a list. Additionally, in Polish, at least, there are some strange cases in which the prefix's normal meaning has nothing to do with the resultant verb, but these instances are relatively few and far between.