On June 18, 2015, Pope Francis will issue the encyclical,Laudato si’. Here are some answers to questions people who aren’t Catholic—like me—may have about the document:

What is an encyclical?

The term encyclical (from the Greek egkyklios, kyklos meaning a circle) refers to a circular letter, that is, a letter that gets circulated to a particular group. A papal encyclical is a letter written by the Pope to a particular audience of patriarchs, primates, archbishops, and bishops of the Catholic Church. Sometimes encyclicals are written to an even narrower group (e.g., the bishops of a particular country) but they normally tend to be for a broader audience. Encyclicals addressed to the bishops of the world are generally concerned with matters which affect the welfare of the Church at large.

What do encyclicals do?

As the Catholic Encyclopedia explains, encyclicals condemn some prevalent form of error, point out dangers which threaten faith or morals, exhort the faithful to constancy, or prescribe remedies for evils foreseen or already existent.

How many encyclicals have been published?

290, so far.

Have encyclicals always been issued by popes?

Although similar documents have been issued since the beginning of the papacy, the first pope to issue a letter and refer to is as an encyclical was Benedict XIV, who released Ubi Primum (“On the Duty of Bishops”) in 1740.

How many encyclicals do popes issue?

It varies by pope.Almost a third of all encyclicals (90) were written by one pope, Leo XIII. This chart by Pew Research shows the number written by every pope since then.

Why is the ing encyclical calledLaudato si’?

The title Laudato si’ is a quotation from the religious song Canticle of the Sun. St. Francis of Assisi, the patron saint of the environment, is said to have written the song that praises God for the creation of the different creatures and aspects of the Earth. The phrase “laudato si” occurs several times in the Latin version of the prayer-song.

The encyclical is also expected to be given the Italian subtitle: “Sulla cura della une,” (On the care of mon home).

What is the topic of this encyclical?

The environment, and more explicitly, climate change. While few people outside the Vatican know exactly what the letter will says, Rev. Robert Sirico explains what we can expect by drawing on Catholic social teaching to provide a helpful framework for understanding the Church’s position on environmental stewardship.

Does the pope actually write the encyclical?

As with most documents by world leaders, Pope Francis has a staff that helps him pose the letter. The first draft was prepared by the Pontifical Council for Justice and Peace. Other church leaders also contributed to the draft. The document was also repeatedly revised and reviewed by the Vatican’s Secretariat of State (and the Congregation for the Doctrine of the Faith.

Is this encyclical considered infallible?

No, it’s not likely to be declared infallible. To meet that standard the letter would have to meet three criteria: 1) the subject is a matter of faith or morals, 2) the pope must be teaching as supreme pastor, and 3) the pope must indicate that the teaching is infallible. No pope since 1870 has designated an encyclical to be infallible.

Are encyclicals considered binding if they are not infallible?

That’s acomplex question. As Stephen Barr says, “Catholic teaching itself distinguishes different levels of authoritativeness for different kinds of teaching and different kinds of Church pronouncements.” Barr has as a brief answer to the question here.

Why is this explainer for “non-Catholics”?

Because all Catholics already know all this stuff.