The jeune ecole (French for "new school") was a Manticoran tactical faction that advocated material-based warfare, led by Admiral Lady Sonja Hemphill. It was opposed to the "historical school", led by Admiral White Haven.
By 1900 PD, large scale warfare had become formalized, with combat between fleets largely being indecisive. Hemphill and her group theorized that the growing number of better weapons and technology would fundamentally alter the nature of combat, making the traditionalist view outdated and outmoded. With Admiral Hemphill's cousin, Admiral Sir Edward Janacek, as First Lord of Admiralty, the jeune ecoles were able to get in top Navy positions.
One of the earliest examples of testing new technologies was the decision by Admiral Hemphill to refit Commander Honor Harrington's light cruiser HMS Fearless with an experimental grav lance. In war games against Admiral Sebastian D'Orville, Fearless was successful in "destroying" D'Orville's flagship, King Roger, by itself. However, the grav lance proved untenable as countermeasures were worked out during the course of the war games. Fearless later defeated the Havenite Q-ship Sirius during the First Battle of Basilisk, but was severely damaged in the process, leading Harrington to harshly criticize Hemphill during the Weapons Development Board review of the battle. (HH1)
Despite the setback, Hemphill and her supporters continued to push for new weapon designs. Prior to the First Havenite-Manticoran War, Hemphill introduced an improved missile launcher for LACs, which was later adapted to missile pods against Hemphill's objections. Admiral Mark Sarnow used these new pods to good effect in the First Battle of Hancock, and they entered common use in the war. (HH3) Later, Hemphill pushed the development of several radical new designs including pod-laying superdreadnoughts, LAC carriers and the new Ghost Rider missiles (As well as a Manticoran version of a Q-ship, a forerunner of the SD(P) and LAC carrier, one of which was commanded by then-Captain Harrington). Although White Haven strongly objected to the rollout of these "untested" weapons at the peak of the war, Harrington supported them (HH7). All three designs eventually gave the RMN a decisive advantage over the People's Navy, and later the Grand Alliance's fleets over the Solarian League Navy.