Musicologist Frits Zwart (1954) is Director of the Netherlands Music Institute in The Hague, an extensive and significant collection of Dutch musical heritage materials. Zwart received his PhD from Utrecht University for a dissertation on Mengelberg (biography 1871-1920). He has published numerous articles related to other aspects of the music history of The Netherlands.

• First period 1871-1895, Second period 1895-1904, Third Period 1904-1911, Entr'acte : Mahler and Strauss, Fourth period 1911-1920, An interim balance, Fifth period, 1920-1930, Sixth periode 1930-1933, Entr'acte: twelve intermezzo's, Seventh period 1933-1940, Willem Mengelberg through the eyes of the musicians, Eigth periode, 1940-1945, Ninth period 1945-1951, Conclusion

"Zwart's account makes fascinating reading and is well worth the considerable investment in time that reading more than 1,000 pages will require. Zwart's work will probably not change your opinion of Mengelberg. I continue to admire his conducting enormously, and at the same time find some aspects of his personality repulsive. This compendious biography makes clear the complexity of the man and helps us understand, if we did not already, that people are complicated beings." - Henry Fogel, Fanfare "Mengelberg is ripe for real rediscovery; this book is an excellent way to start a reappraisal of him." - Chris Walton, The Wagner Journal, 2020 "I can think of few musical performer biographies in recent decades which have covered their subject in such a fastidious and all-embracing manner as this one devoted to Mengelberg." - John Hunt, Musical Opinion October 2019 "This book is the most thorough and well-researched monograph about any major conductor that I have ever come across. (...) Conductor Willem Mengelberg, 1871-1951 should be read by everyone who is interested in the art of conducting, in musical performance, and the musical business in the 20th century. It is highly recommended." - Gregor Tassie, Musicweb International, August 2019 5 stars - "A huge undertaking for Zwart carried out with insight, zeal and careful management to create books that make an indivisible pair, dippers-into and page-turners. These publications (which appear to now be a singular issue) document Mengelberg’s incident-packed life (music and otherwise), colourfully vivid for our own time." - Colin Anderson, Classical Source, August 2019 "As a biographer, Frits Zwart has done more than an excellent job in exploring the life, works and times of Willem Mengelberg. In his critical biography even sensitive subjects are handled with great care, with not the slightest hint of covering something up. On the contrary, Zwart's clear writing and his aversion of shunning any unpleasant detail give the reader a deeply rooted and multi-layered insight in one of the most controversial personalities and greatest musical minds in the world of classical music to date." - Aart van der Wal, Opus Klassiek, August 2019 "Whilst it is an academic work, it is one which is admirably readable, and the research undertaken by Zwart is exemplary, with extensive footnoting to orchestral board meetings, contemporary newspapers, private correspondence and interviews (...) *Conductor Willem Mengelberg: Acclaimed and Accused* is a colossus of researched biography, one which will open up the life and times of this great yet complex musician to the contemporary reader." - Brett Allen-Bayes, Limelight, Australia's Classical Music and Arts Magazine