The Rebbe wants us to study
Tanya Ba’al Peh.
Take a look at some quotes from Sefer HaSichos and Igros Kodesh:
“We have already spoken in length abouth being fluent in the first 12 Perakim of Tanya. This is a special Segula, and refines the soul. In addition, the person will have Torah in his head…”
Igros Kodesh Volume 4 page 269:
“A Perek Tania Ba’al Peh brings an abundance of blessing and success”
Sefer Hasichos 5691 page 168:
“I want to reveal a little secret. In this year, everyone should learn by heart the first 12 Perakim of Tania, with specific attention to every letter, from the introduction “Aleichem Ishim Ekra” until Perek Yud Gimmel. When you go to sleep at night, when you wake up, and when you go in the street, you should review this in speech and in thought.”
Igros Kodesh of the Rayatz Volume 13 page 438:
“In regards to learning Tanya Ba’al Peh, you should set times to learn an average of one Perek within two weeks, and for an especially long Perek, within 3 weeks to a month. And it is important to review in detail what you’ve learned, and Hashem will help in Gashmiyus and Ruchniyus.”
Igros Kodesh of the Rayatz Volume 13 page 519:
“Hearing of the Bekius in Tanya Ba’al Peh until Perek Lamed Zayin made me very, very happy. And the main thing is to review every available moment and while walking in the street, and he should be diligent in it as much as he is able before going to sleep, and he should be very careful with each letter, and as much as he is able, should continue to learn more…It is crucial to be fluent in all the details, and to review well, at every opportune moment, and before sleeping.”
Tanya Ba'al Peh 