In this encyclical from 1981, Pope John Paul II advances what I would call some Christian "guidelines" for theological reflections on work and, indeed, a spirituality of work. In these brief guidelines, JP II is setting up the boundaries for how Christians can regard the meaning of their work and their role as workers. In this he relies upon Catholic social teaching (especially from "Rerum Novarum," Pope Leo XIII's 1891 encyclical on working conditions and social righteousness), the documents of Vatican II (especially "Gaudium et Spes"), and his own "personalist" philosophizing (as JP II - Karol Wojtyla - was an accomplished professor of philosophy in Poland after World War II).
What I especially appreciated from this encyclical is JP II's insistence that the subjective aspect of work, that is, the worker himself or herself, is determinative of work's value; in other words, labor is greater than capital - infinitely greater, for each of us is made in the image of God, the First Creator, and in our creating we participate in God's working and demonstrate the God-image within us. As part of this, JP II also defends the dignity of all work, however "low" it may be in popular society. This also leads him to point out that those with any kind of disabilities deserve the chance to exercise their right to work, and that employers and governments must make every effort to remove obstacles in the way.
In a world where governments are seriously contemplating a universal wage to give to subjects, it's interesting to read JP II's thoughts on unemployment and underemployment. "The role of the agents included under the title of indirect employer is to act against unemployment, which in all cases is an evil, and which, when it reaches a certain level, can become a real social disaster." It's a social disaster not because people have no money (capital is always less than the dignity of the laborer himself or herself), but because in work we humans fulfill our original calling in the Garden, and we have the opportunity through our work to love neighbor, exercise dominion over the earth, and prepare for the coming Kingdom. The meaning of work stretches back to the distant past, embraces present realities, and points ahead to the future. Work, as JP II points out, "transforms nature and fulfills human nature." This fulfillment of human nature is often subordinated in contemporary discussions where lawmakers just believe that people want money and not work.
It's also worth noting that in the tradition of Catholic social teaching, there is really nothing that is off-limits. The pope writes at length on the importance of labor unions, strikes, fair pay, safety in the workplace, international laws for workers, etc. Even though this is a theological work, JP II continually has his eyes on practical measures throughout it.