What has the author Samuel de Constant written?

There is no author named "Samuel de Constant". It's possible you're thinking of Benjamin Constant, a French writer, philosopher, and politician.

Some of his most notable works include:

* Adolphe (1816): A semi-autobiographical novel exploring romantic love and the complexities of human relationships.

* Principles of Politics Applicable to All Governments (1815): A political treatise arguing for individual liberty and limited government.

* Religion Considered as a Political Institution (1825): An essay exploring the relationship between religion and politics.

* On the Spirit of Conquest and Usurpation (1814): A philosophical work examining the nature of power and domination.

If you meant someone else, please clarify the name and I can try to help further.