This collection of refereed papers celebrates the contributions, achievements, and progress of female mathematicians, mostly in the 20th and 21st centuries. Emerging from the themed paper session The Contributions of Women to Mathematics: 100 Years and Counting at MAA's 2015 MathFest, this volume contains a diverse mix of current scholarship and exposition on women and mathematics, including biographies, histories, and cultural discussions. The multiplicity of authors also ensures a wide variety of perspectives. In inspiring and informative chapters, the authors featured in this volume reflect on the accomplishments of women in mathematics, showcasing the changes in mathematical culture that resulted as more women obtained tenure-track and tenured academic positions, received prestigious awards and honors, served in leadership roles in professional societies, and became more visibly active in the mathematical community. Readers will find discussions of mathematical excellence at Girton College, Cambridge, in the late 19th and early 20th centuries; of perseverance by Polish women in mathematics during and after World War II and by Black women in mathematics in the United States from the 1880s onward; and of the impact of outreach programs ranging from EDGE's promotion of graduate education to the Daughters of Hypatia dance performances. The volume also provides informative biographies of a variety of women from mathematics and statistics, many of them well-known and others less well-known, including Charlotte Angas Scott, Emmy Noether, Mina Rees, Gertrude Cox, Euphemia Lofton Haynes, Norma Hernandez, Deborah Tepper Haimo, and Teri Perl. These essays provide compelling reading for a wide audience, including mathematicians, historians of science, teachers of mathematics, and students at the high school, college, and graduate levels. Anyone interested in attracting more girls and women as students, faculty, and/or employees will also find this volume engaging and enlightening.