From Chapter 4:
But to turn from this worthy Exeter citizen to more famous names: I do not know of any good evidence as to whether or not Cromwell smoked, although he is said to have taken an occasional pipe while considering the offer of the crown, but John Milton certainly did. The account of how the blind poet passed his days, after his retirement from public office, was first told by his contemporary Richardson, and has since been repeated by all his biographers. His placid day ended early. The poet took his frugal supper at eight o'clock, and at nine, having smoked a pipe and drunk a glass of water, he went to bed. Apparently this modest allowance of a daily evening pipe was the extent of Milton's indulgence in tobacco. He knew nothing of what most smokers regard as the best pipe of the day—the after-breakfast pipe.

From Chapter 6:
But so early as 1655 there is a sign of change of custom—a change, that is, in the direction of restricting and limiting the hitherto unbounded freedom granted to the use of tobacco. The London Society of Apothecaries on August 15, 1655, held a meeting for the election of a Master and an Upper Warden; and from the minutes of this meeting we learn that by general consent it was forbidden henceforward to smoke in the Court Room while dining or sitting, under penalty of half a crown.