Short answers, pulled from the story.
Hessel Gerritsz was a Dutch engraver, cartographer, and publisher who began his career as an apprentice to Willem Jansz Blaeu in Alkmaar. He established his own printing workshop on Nieuwezijds Voorburgwal by 1610 and produced influential maps of the South Pacific.
Hessel Gerritsz was appointed the first exclusive cartographer of the Dutch East India Company on the 16th of October 1617. Petrus Plancius recommended him for this strategic position despite not getting along with senior Willem Blaeu.
In 1628, Hessel Gerritsz added François Thijssen's 1627 charting of Australia's south coast making it the first map showing an outline of Australia. His earlier work from 1622 showed the first part of Australia charted by Willem Janszoon in 1606 which was considered part of New Guinea but called Terra Australis Incognita on the map.
Hessel Gerritsz had eight children together before his wife Geertje Gijsberts died before 1624. He died in 1632 at age 54 and was buried in the Oude Kerk on the 4th of September.
Hessel Gerritsz is considered by some unquestionably the chief Dutch cartographer of the 17th century despite strong competition because his work established foundations for future mapping efforts across multiple continents. All charts and logs from returning VOC merchants and explorers had to be submitted to him during his tenure until his death after which the Blaeu family held the position starting with Willem Jansz until 1705.