At the invitation of Professor Meldola, F.R.S., Professor of Chemistry at the Finsbuiy Technical College of the City and Guilds of London Institute, I delivered at that College, in the winter of 1889, a course of six lectures on the Science of Brewing. At the conclusion of the course, those who had honoured me by their attendance were so good as to suggest to me the desirability of publishing the lectures in book form. On a consideration of that suggestion, I thought that such a publication might perhaps be of some service; and it was then my intention to limit myself to a re-perusal of the manuscript, and to its publication as such, after only those alterations had been made which seemed necessary from the literary standpoint On commencing the work, however, I soon came to the conclusion that to continue on those lines would be unsatisfactory: partly because the scope of the work would thus be very limited; partly because researches published since the date of the lectures threw an entirely new light upon several important matters, more especially upon the products of starch-conversion, and upon the changes occurring during the germination of the cereals. I therefore determined to go over the ground afresh, taking my lectures only as a basis for a more complete and general work than I had at first contemplated. Such a plan, however, involved more leisure than I had at my disposal, and I was obliged to seek assistance.