This is the approved revision of this page, as well as being the most recent.
Do Not be Discouraged by the Breadth and Length of Halacha
Notwithstanding the vastness of the Halacha, one must not lose sight of the goal. A person must be familiar with the basic laws that are relevant on a daily basis, e.g., blessings, prayer, and Shabbat. If one is not familiar with the basics in these areas, it is impossible to strive to fulfill the mitzvot in these areas by merely observing others or by guessing. It is highly advisable to find a simple book that outlines the Halacha (or this website) and to set up a schedule of study to enable one to study on a regular basis. (See the introduction to volume 3 of the Mishna Brurah.)
Your Question May Not be the Same as the General Halacha
The purpose of this website is certainly not a substitute for asking questions to your local rabbi. The website is intended to provide the English-speaking Jewish community with summaries of relevant halachot. Clearly, the site does not always provide answers to your specific question, and for that it is important to either learn the halachot properly from the sources or to ask your local rabbi. Often, a single differentiating factor may apply in your case that can change the halacha from permitted to forbidden or vice versa.
There are countless Halachot that have significant disagreements between the contemporary authorities. It is of the utmost importance to note that it is not the role of this website to arbitrate between two major poskim or gedolei hador. Therefore, in the event of a dispute, it is imperative to either consult with your local rabbi or to choose one opinion and consistently follow it. It is unacceptable to simply choose to be lenient or stringent in every dispute due to a lack of knowledge (See Eruvin 6b). Rather, one must appoint for oneself and one's family a rabbi, whether it is a local one or a book that one can consult and adhere to without fail. (See Pirkei Avot 1:6 where Rabbi Yehoshua Ben Prachya says one should appoint for oneself a Rabbi).
If a particular halacha only has one opinion when there are a number of other dissenting opinions, this is usually unintentional. We do not intentionally leave out the opinion of legitimate Orthodox halachic opinions and we welcome the addition of all different opinions and minhagim. As the project grows, it is very possible and likely that certain halachot will be one-sided until someone adds the dissenting opinions. If you are aware of another opinion that is not displayed on this site, please add it or let us know. Additionally, for the sake of simplicity, we encourage summarizing the groups of opinions in the top halachic summaries. However, the details and the nuances in each opinion may and should be presented below in the footnotes.