To the most Distinguished and Worthy gentleman and most Skilled Mathematician, Dr William Oughtred Rector of the church of Aldbury in the county of Surrey

Here for you at last (most distinguished gentleman) is now the whole of that work of which I gave hope in that proposition on circle measurement that I gave you in its stead in print last Easter (see Figure 1). For since, by custom, when one puts something out in public, it ought to be dedicated to someone, I thought to seek not only a great gentleman but a great mathematician to whom I might offer it. And therefore I saw that to none other greater than you can that easily be done, who is among mathematicians most deserving, and also by whose writings I readily confess that I have profited: who indeed in your Clavis mathematicae, though not a large work, have there taught both briefly and clearly, what we seek in vain in the large volumes of others.1