This was the period that produced the Quakers and a number of the most vigorous developments of Puritanism, in which the foundations of modern republicanism were laid, and in which the project of a world league of nations--or rather of a world state--received wide attention. And the student of Comenius will find in him an active and sensitive mind responding with a most interesting similarity to our own responses, to the similar conditions of his time. He has been distressed and dismayed--as most of us have been distressed and dismayed--by a rapid development of violence, by a great release of cruelty and suffering in human affairs. He felt none of the security that was felt in the eighteenth and nineteenth centuries of the _certainty_ of progress. He realized as we do that the outlook for humanity is a very dark and uncertain one unless human effort is stimulated and organized. He traced the evils of his time to human discords and divisions, to our political divisions, and the mutual misconceptions due to our diversity of languages and leading ideas. In all that he might be writing and thinking in 1921. And his proposed remedies find an echo in a number of our contemporary movements. He wanted to bring all nations to form one single state. He wanted to have a universal language as the common medium of instruction and discussion, and he wanted to create a common Book of Necessary Knowledge, a sort of common basis of wisdom, for all educated men in the world. Now this last is the idea I would like to develop now. I would like to discuss whether our education--which nowadays in our modern states reaches everyone--whether our education can include and ought to include such a Book of Necessary Knowledge and Wisdom; and (having attempted to answer that enquiry in the affirmative) I shall then attempt a sketch of such a book.