The Advice to Hartlib was a treatise on education, written by Sir William Petty (1623–1687) in 1647 as a letter to Samuel Hartlib. and published in 1647/8. It was the first printed work by Petty and covers a total of 31 pages. William Petty was educated in France and in Holland, and returned to England in 1646, to study medicine at Oxford University. By that time he had close contacts with scientists like Thomas Hobbes. He developed an instrument for double-writing and became friends with Samuel Hartlib and Robert Boyle. Samuel Hartlib (c. 1600 – 1662) had a profound interest in many fields of science and was especially active in creating (written) contacts with a number of persons, often scientists, part of whom were members of the Hartlib Circle. He had a clear vision on the importance of education and the spread of knowledge. In 1644 John Milton (1608–1674) wrote his tract Of Education as a letter to Hartlib. Hartlib himself wrote a pamphlet concerning education in 1647. The Advice to Hartlib was William Petty's contribution to the debate. Bibliographical information 26 p. The pamphlet was reprinted in The Harleian Miscellany, London 1745, vol. vi, pp. 1–13 and London 1810, vol. vi, pp. 1–14. In 1862 large parts of the text were reissued in – English Pedagogy, under the caption of 'Plan of an Industrial School'. Parts of the Advice were also reproduced in (1954) – Three Thousand Years of Educational Wisdom. Background In the days that Petty published his treatise, Samuel Hartlib was the patron of up-and-coming young men. He had a stimulating influence on many others in persuading them to publish their ideas. In 1644 for instance, John Milton (1608–1674) wrote his tractate Of Education as a letter to Hartlib. In 1647 Hartlib himself published a tract, advocating the establishment of an 'office of public address'. This office would have as a main function the dissemination of information about new inventions. William Petty, aged 27, got involved in this debate about education, and published his Advice. Contents The first page of Advice to Hartlib is a kind of advertisement for an instrument for "double writing" that was invented by Petty (and that would again be introduced in his pamphlet Double Writing in 1648), "which is not strictly relevant to the rest of the pamphlet." On the next page, with the title "To his honoured friend Master Samuel Hartlib",