The teachers: Since childhood, Imam Abu Yusuf already have a strong interest in science, especially the science of Hadith. He narrates, among others from his teachers that Hisham ibn Urwa, Abu Ishaq al-Shaybani, Ata 'ibn Saa'ib and others. In fiqh, he learned to Muhammad ibn Abdur Rohman bin Abi Laila who is familiar with Ibn Abi Laila. But he is very interested in the jurisprudence as well as his teacher and friend of Imam Abu Hanifah (150 H). Because of his interest to the jurisprudence of Imam Abu Hanifa is so large, in addition because the strong encouragement of Imam Abu Hanifa himself, so he was compelled to spread throughout the Hanafi Abbasid territory. Even be said that was he the first and most responsible for the development of the Hanafi jurisprudence of Islamic society. This ni because he was appointed as the Chairman of the judges (Qodhi al-Qudhot) by the caliph Harun al-Rosyid, this position is actually the first office in the Islamic justice system, so freely to issue fatwas and decide the case by referring to the Hanafi jurisprudence. At the same time he got the freedom to seek the pembatu which of course is in line with fikihnya own.

His works:
1. Kitab al-Atsar. A book that collects the traditions narrated from the teacher and also from his father. Traditions collected in this book is not all muttasil (continued until to the Prophet Muhammad) only until Sebagain to friends (mauquf) or to Tabi'in (mursal).
2. Book deviation Ibni Abi Abi Hanifa wa Laila. Seeing the title already crossed that this book collects the differences in the fiqh of Abu Hanifa and Ibn Abi Laila who is also a teacher of Imam Abu Yusuf.
3. Kitab ar-Radd ala al-Siyar Auza'i This book is a set of arguments-arguments against the Imam Abu Yusuf al-Auza'i opinions surrounding the war and jihad.
4. Kitab al-Khoroj. This book is a book of his most important and famous that beat the fame his books another. With this book he is crowned Fakih and classical Muslim economists.
According to a scholar Ibn Najm Hanafiyah, there are many more books written by Imam Abu Yusuf, other than those already mentioned above, for example as-Sholah book, Kitab az-Zakah, and others.

A glimpse of the Kitab al-Khoroj.
This book was written by Imam Abu Yusuf at the request of the caliph Harun al-Rosyid to guide you in collecting state revenues or income from taxes, zakat and jizya. As was said by the Imam Abu Yusuf, "Verily Commander of the Faithful Harun al-Rosyid (may Allah strengthen his power) has asked me to write a general book a guide in gathering khoroj, usyur, zakat and jizya". Given the title and the contents of this book this book it can be classified as a book Public Finance in terms of modern economics.

Khoroj is the land tax which is controlled by the Muslims either because of war or because the owner entered into a treaty with the Muslims. They remain the owner of its lands, but by paying taxes (khoroj) a certain amount to the Baitul Mal.

Usyur are plurals usyr means a tenth or 10 per cent. He refers to the level of agricultural charity and customs that apply to the Muslim traders and non-Muslims across the region daulah Islamiyah. In agriculture there are problems due the following conditions: if penglelolaan soil using irrigation techniques were then nisf Zakah al-usyr (5 per cent) whereas if the irrigation management is using rainwater is then Zakah usyr or 10 per cent. In recent history, customs of Muslim traders, and ahlu dhimma ahlu differentiated harb. Muslim traders charged rub'ul usyr (2.5 per cent), ahlu dhimma nisf al-usyr (5 per cent) and the Ahl al-harb usyr (ten per cent).

Jizya is a head tax to be paid by non-Muslims who live and be protected in an Islamic state. Prophet Muhammad set a poll by his friend Muadz bin Jabal when he was sent to Yemen as many as one dinar every person who has consent. This size does not seem to be standard conditions proved Umar ibn jizya Khottob pick as many as 4 pence or 40 dirhams.

Apart from charity, and ghonimah fai 'incomes above the third is a source of major income sources for daulah Islamiyah. Kitab al-Khoroj this is the first book that collects all revenue daulah Islamiyah and the posts and expenditures based on the Sunnah kitabullah Apostles.

Begins with good advice to the caliph Harun al-Rosyid, Imam Abu Yusuf stressed that the authorities realize that the mandate of power is hard but if done with full trust is also a source of very great reward. The main task of the authorities is to eliminate injustice felt by the people and meet all their needs and unseen. (Pp. 3-17)

In collecting zakat and other income, the authorities advised to choose people who can be trusted (trust), thorough and critical. This is all expected to be the free union of all leaks so that optimal results can be realized for the benefit of citizens. (P. 132)

According to Imam Abu Yusuf, Islamic economic system clearly follow the principles of market mechanism to provide optimum freedom for the actors in it, namely producers and consumers. He presented a atsar that many citizens complain to the caliph Umar bin Abdul Aziz as prices soared in their time. Umar bin Abdul Aziz answered their complaints by saying that the previous rulers (before him) has been collecting taxes from ahlu dhimma with levels that exceed the carrying capacity. While his poll tax burdens not limited to his own ability but because of "the Prophet Muhammad was sent to a caller to Islam and not be a tax collector." If, for any reason other than the monopoly, hoarding or unilateral action is not reasonable from the manufacturer, the price increase occurs in the economy, the government can not intervene to fix prices. Fully pricing played by forces of demand and supply in the economy. (Pp. 131-132).

Kitab al-khoroj different from the books of classical Islamic economics was born from a generation that close to him like a book of al-Ubaid Abu amwal works whose content is a collection of Hadith and related atsar economics, finance and business. The book is in addition to describing the traditions of the Prophet SAW associated with chapters state revenue and expenditure in detail and systematically, also spread the thoughts of Imam Abu Yusuf himself in these matters which is an expression of opinion notwithstanding madhhab of Abu Hanifa in his many different issues teacher. Although this book was written more than 1200 years ago, but still very relevant to serve rujuakan in economics, finance and trade in modern times now. Even can be used as a guide, reference and complement the government's fiscal policy and monetary and economic development in general.