<p><br></p><p><span style="color: rgba(0, 0, 154, 1)">This Festschrift is dedicated to Tom Maibaum on the occasion of his 70th birthday and on the occasion of his retirement. The Festschrift is also a follow up to the International Symposium on the Mathematics of Software Engineering organized by the Department of&nbsp;&nbsp;Computing of the University of Rio Cuarto,in February 2019.</span></p><p><span style="color: rgba(0, 0, 154, 1)">&nbsp;</span></p><p><span style="color: rgba(0, 0, 154, 1)">The Festschrift contains contributions by Tom's former students, colleagues, and friends. These contributions address research questions and problems in the general area of Formal Methods for Software Engineering - an area which Tom has spent most of his academic life working on.</span></p><p><span style="color: rgba(0, 0, 154, 1)">&nbsp;</span></p><p><span style="color: rgba(0, 0, 154, 1)">There are many reasons for publishing a Festschrift. Tom's academic merits alone would suffice for publishing this one. This Festschrift is also a token of appreciation.&nbsp;We wanted to make use of the opportunity to thank Tom for the impact he has had in the academic careers of many of his colleagues and collaborators, and especially in those of his former students.</span></p>