Thanks for your answer.

As a non-Muslim two things are of interest to me.

abuayisha wrote: Are, then, the scholars of fiqh the contemporary authoritative and/or authentic interpreters of Sharia law? There is much debate on this issue.

1.  Is there a published/promulgated collection of agreed upon laws that are considered authoritative and binding on Muslims in general?  For example, there is a promulgated code of laws and court precedents that are a matter of public record which is binding law in America.  Analogously, there is a code of canon law in the Catholic Church that is binding and a matter of public record.

Or is any legal opinion of a scholar an acceptable interpretation of Sharia Law? Wide debate on this question.

1.  Is there a published/promulgated collection of agreed upon laws that are considered authoritative and binding on Muslims in general?  For example, there is a promulgated code of laws and court precedents that are a matter of public record which is binding law in America.  Analogously, there is a code of canon law in the Catholic Church that is binding and a matter of public record.

Yes, Shariah is essentially canon law, where Allah or His Prophet clearly states an injunction all Muslims would be obliged to follow.  For example Muslims are now fasting the month of Ramadan and in the Quran Allah says;

abuayisha wrote: 1.  Is there a published/promulgated collection of agreed upon laws that are considered authoritative and binding on Muslims in general?  For example, there is a promulgated code of laws and court precedents that are a matter of public record which is binding law in America.  Analogously, there is a code of canon law in the Catholic Church that is binding and a matter of public record.   Yes, Shariah is essentially canon law, where Allah or His Prophet clearly states an injunction all Muslims would be obliged to follow.  For example Muslims are now fasting the month of Ramadan and in the Quran Allah says; �Strictly observe the fast till nightfall� (Surah 2 Ayat 187) "...And it is better for you that ye fast, if ye only knew." (Q 2:184) "So whoever of you is present in the month, let him fast�. (Surah II.185) �And that ye fast is better for you, if you did but know.� (Surah 2 Ayat 184) "...whoever witnesses the Month of Ramadan should fast through it..." Q (2:185) "O believers! You prescribed the Fasting (Al- Siyam) as it was prescribed for those before you, and you achieve piety" (Surah II. 183) All scholars would therefore agree Muslims must fast during this month unless sick, pregnant or traveling, etc., which are excuses given in other texts of Quran and Sunnah.   While I am sure that there is a consensus of some (perhaps a majority of) Muslim scholars that terrorism and military conquest are not valid means of spreading Islam, if a particular scholar or another consensus affirmed that they are valid means,  would that make them legitimate?   I define �terrorism� as premeditated, politically-motivated violence perpetrated against noncombatant targets by subnational groups or clandestine agents, usually intended to  intimidate or coerce a government or civilian population.  Innocent noncombatants are deliberately targeted as a matter of strategy. Well there is no doubt in my mind what you have articulated above is the fiqh position of Al Qaeda and its followers, and yes they believe what they are doing is legitimate.  Saudi Arabia has opened several prison camp schools in an effort to re-educate those found to have this extreme and dangerous legal position.  Sadly it exists, but indeed it's a fringe position having no widespread legitimacy.

Thank you for a thorough and informative answer.

I included in my question "military conquest" (in addition to terrorism) as a means of spreading Islam, e.g, the invasion and conquest of the Visigothic Kingdom of Spain by Muslim forces in the 8th century.

Is that considered in Sharia Law a legitimate means of spreading Islam?

Here is a link that explains about Islamic Shariah. You may include this in further reading: 

Well, unfortunately I haven�t a clear and factual account of circumstances surrounding this invasion, however much of �military conquest� would fall under fiqh, and there must be a Muslim ruler (Caliphate) present.  Unlike what exist today where you have Muslim nation-states.  Sharia seeks to protect borders, keep the Arabian Peninsula free, and secure the rights of people to hear the word of Islam.  As already mentioned, there is no compulsion in religion, therefore once hearing the message of Islam people are not forced to accept Islam or die.  Sharia does not obligate Muslims to fight non-Muslims simply because of their disbelief.  Jihad is not a fight against the whole world, and in contemporary times without the presents of a single Muslim ruler it is defensive in nature at best.

abuayisha wrote: I included in my question "military conquest" (in addition to terrorism) as a means of spreading Islam, e.g, the invasion and conquest of the Visigothic Kingdom of Spain by Muslim forces in the 8th century.   Is that considered in Sharia Law a legitimate means of spreading Islam?   Well, unfortunately I haven�t a clear and factual account of circumstances surrounding this invasion, however much of �military conquest� would fall under fiqh, and there must be a Muslim ruler (Caliphate) present.  Unlike what exist today where you have Muslim nation-states.  Sharia seeks to protect borders, keep the Arabian Peninsula free, and secure the rights of people to hear the word of Islam.  As already mentioned, there is no compulsion in religion, therefore once hearing the message of Islam people are not forced to accept Islam or die.  Sharia does not obligate Muslims to fight non-Muslims simply because of their disbelief.  Jihad is not a fight against the whole world, and in contemporary times without the presents of a single Muslim ruler it is defensive in nature at best.

(1) So if there were a single Muslim ruler, jihad could be offensive in nature with respect to surrounding cultures and/or nation-states?  This does seem to be the case in the first 150 years of Islamic history.

(2) If a single Muslim ruler were to arise again, would offensive jihad be legitimate against surrounding cultures and/or nation-states again?

(3) With respect to the conquest of Christian lands, while Christians were not forced to accept Islam or die, they did live in a vastly inferior position under the newly established Muslim government in the lands that were once their own.  Depending on the ruler�s whim, they had to pay a special tax; could not spread their faith by preaching; often had to wear humiliating signs on their clothing; endured severe restrictions on public expressions of their faith, construction of churches; etc. Would this practice continue?

As a english speaking non-muslim that recently started reading/studying quran, Quran Explorer is an EXCELLENT resource.  I would recommend this to anyone that has a desire and willing to learn.