Оба предложения правильные. Разница в том, что они описывают немного различные ситуации, например: "Я хочу читать эту книгу" (здесь акцент сделан на том, что вы хотите выполнять действие, т.е. хотите заниматься чтением этой книги); "Я хочу прочитать эту книгу" (здесь акцент сделан на том, что вы хотите выполнить действие, т.е. хотите завершить процесс чтения).

Хочу от себя добавить, что данный пример "хочу читать эту книгу" может и правильный, но такое вы врядли услышите. Скорее вы услышите "хочу ПОчитать эту книгу". И это будет означать, что вы хотите провести какое-то время за чтением этой книги. "Хочу ПРОчитать эту книгу". Трудно объяснить, действительно. Это даже не совсем завершить процесс чтения, по моему. Просто завершить процесс чтения будет скорее "Хочу ДОчитать эту книгу". Скорее тут вы хотите стать обладателем знания содержимого книги. Хмм... Я думаю легче всего будет понять с на примерах. Я хочу немного почитать эту книгу. I want to spent some time reading this book. ПОчитать - seems like more about time you want to spent reading. ПОчитал книгу - spent some time reading a book. Я хочу сегодня ДОчитать эту книгу до конца. I want to finish reading this book today. Дочитать - is more like about achieving final result, reaching "the end" words, finishing reading. Ты ДОчитал книгу - You have finished reading the book. Я хочу ПРОчитать хотя бы половину этой книгу до завтра. I want to read at least half of this book till tomorrow. This is more like about achieving knowlege/or whatever this books consist of or part of it. Ты ПРОчитал книгу - You have read whole book

Either can be correct based on the context. English has no real equivalent, so I am still trying to understand this myself. This illustrates "verb aspect" - imperfective (читать) or perfective (прочитать). Imperfective verbs imply that the action is ongoing. Perfective verbs have a connotation of completion or incrementation. I'm still looking for an excellent explanation by a native Russian speaker, but hopefully this helps a bit. http://www.russianlessons.net/grammar/verbs_aspect.php

Aaron gave you the right answer. Perfective means that the action has been completed or that it will be completed. Imperfective means that the action was performed and it continued to be performed for a period of time, which can be past present or future. The following videos can help you understand more the tenses of Russian: http://www.youtube.com/watch?v=fwFwzV0mJyc http://www.youtube.com/watch?v=FRXft10St94 http://www.youtube.com/watch?v=Qd5rJ3SlbEA I hope this helps you.

The perfect forms of verbs in Russian are not formed by adding a "po-" prefix. They are not even formed by any single prefix in all the cases. Verbs either get a "pro-" prefix, some other prefix, or simply have another form of their own. Also, for some actions, another synonymous prefix, "do-", can be added to mean more precisely that something was done to the end, until the end, until a result. Examples. Russian: - Ya chital 'Voynu i Mir' vchera, no ne dochital. - A ya prochital v 6 klasse. English: - I read "War and Peace" yesterday, but didn't finish reading it. - And I read it (completely) in the 6th grade. Here, like in many cases, "prochital'" and "dochital'" mean basically the same. Though, for example, "idti", "proyti" and "doyti" mean, respectively, "go", "go through", "go up to / until ...". You can see a slight difference in the meaning of "pro-" and "do-". And for an example of verbs that have their own perfect forms: uchitivat' -> uchest' (take into account /imperfect, as in "I always consider students' opinions"/ -> take into account /perfect, as in "yes, I have taken into account all of this in the report", can't really be used in present tense/ uchit' -> vyuchit' (learn /imperfect/ "Ya uchu russkiy" - "I learn / am learning Russian" -> learn /perfect, again, rarely used in present tense, but here are examples for both: "Ya vyuchil kitayskiy" - "I have learned Mandarin", "Ya vyuchivayu odin yazik za shest' mesyacev" - "I learn (completely) 1 language in 6 months") Now, "pochitat'" actually means "to read for some time, to read for a while". Most verbs with an added "po-" bear that meaning. Cheers.