The first chemistry book was The Sceptical Chymist by Sir Robert Boyle (1661), to whom was attributed: “I should have greater hope ... if men should make a greater distinction between that which they know and that which they think they know.” His lament resonates with contemporary scientists’ concerns for data integrity. This book contains essays on data integrity. Data integrity is the most basic element of work in any scientific discipline. Nothing of lasting value in the hard sciences (physics, chemistry, biology, astronomy, et al.) lacks integrity in the data used to support the premises, the logical arguments proposed, and the conclusions drawn. The point of validation is, after all, to ensure that all results obtained and reported are true.