“ELLEN GALLAGHER was born in 1965 in Rhode Island, the daughter of an African-American father with ties to Cape Verde in West Africa and an American-Irish mother. Now she divides her time between New York and Rotterdam. Ms Gallagher mines sci-fi, marine biology and black history for her art, variously making use of cut-up paper, pencil, plasticine, printed matter, rubber, gold leaf and photogravure. It is out of this rich interbreeding of method and materials that her astonishing work arises.This summer two new Gallagher exhibitions will open, one on each side of the Atlantic. A substantial survey at Tate Modern in London will be followed by a 20-year retrospective at the New Museum in New York.The first room at the Tate Modern show has been covered with ruled writing paper, a reminder of the importance that the line and the grid play in Ms Gallagher’s work and of the inspiration of minimalist artists such as Agnes Martin and Sol LeWitt. This humble papering provides a formal background for her work and helps steer it away from pomposity. But there is much more to Ms Gallagher’s work than linear scaffolding—much to be…”