Because he travelled a lot throughout his life, Vauban got to know the French kingdom very well. He was a fine observer with the ability to analyse and understand what he saw. .He wrote down all the remarks, reflections and questions borne from his extensive travels.

A forerunning environmentalist

Throughout his journeys, Vauban noticed that forests in France were steadily shrinking. In his Treatise of forestry, he recommended a rationalised organization of forests through properly planned tree felling, copsewood techniques and tree nurseries to ward off the inevitability of deforestation. All of this advise can be found in his Treatise of forest culture which was compiled in the Oisivetés.

Vauban also devoted a lot of his time studying water and waterways. He made a study of the Languedoc Canal on Louvois' request ( Report on the Languedoc canal- Mémoire sur le canal du Languedoc)

He also wrote a report about inland navigation (Report on inland navigation- Memoire sur la navigation des rivières)

All of his reports were fully illustrated and contained figures and statistics. Through these writings, Vauban aimed at a better management of the forests and the improvement of inland navigation, with a view to increasing the prosperity of the kingdom.

Vauban and economy :

Vauban was very much concerned with his soldiers' conditions of living, as well as those of the people. But, more generally, he was concerned with the overall prosperity of the kingdom. 

For fair taxes :

In his Project for a royal tithe, and in the Geographical description of the Vézelay district, Vauban stresses all of the injustices the people undergo all over the kingdom. He informs, advises the King and recommends the creation of an income tax for everybody, without any exception granted for the church, or the aristocrats.

His royal tithe is based on the statistical data that he collected throughout the kingdom. His Project for a royal Tithe makes him one of the fathers of modern statistics.

Building as an art :

As Vauban was concerned with the quality of military buildings, as well as with public finances, he wrote a list of advice in the form of maxims (143 maxims for all builders to observe - 143 maximes bonnes à observer pour tous ceux qui font bâtir). They deal with foundation digging, masonry, carpentry… etc...

Vauban and the colonies :

In his treatise called How to restore our American colonies (Moyen de rétablir nos colonies d'Amérique), Vauban suggests different means of developing the French colonies.. 

According to Vauban, the economic development of the colonies implies the steady increase of their population. Vauban demonstrates this argument by making a projection of the increase of the population of Canada until 1970 !