The Democratic National Committee has released the names of the 20 presidential candidates who have qualified for the first debates on June 26 and 27 in Miami.Why it matters: The back-to-back nights of debates will feature one of the most diverse and crowded Democratic fields in history. Four candidates — Montana Gov. Steve Bullock; former Alaska Sen. Mike Gravel; Miramar, Florida Mayor Wayne Messam and Massachusetts Rep. Seth Moulton — did not qualify.The participantsSen. Michael Bennet of ColoradoFormer Vice President Joe Biden*Sen. Cory Booker of New Jersey*South Bend, Indiana Mayor Pete Buttigieg*Former Housing Secretary Julián Castro*New York City Mayor Bill de BlasioFormer Rep. John Delaney of MarylandRep. Tulsi Gabbard of Hawaii*Sen. Kirsten Gillibrand of New York*Sen. Kamala Harris of California*Former Gov. John Hickenlooper of ColoradoGov. Jay Inslee of Washington*Sen. Amy Klobuchar of Minnesota*Former Rep. Beto O'Rourke of Texas*Rep. Tim Ryan of OhioSen. Bernie Sanders of Vermont*Rep. Eric Swalwell of CaliforniaSen. Elizabeth Warren of Massachusetts*Author Marianne Williamson*Entrepreneur Andrew Yang**The candidates with asterisks next to their names qualified through both polling and by reaching the 65,000 donor threshold.What to watch: The campaigns that qualified will participate in a random drawing at 30 Rock to determine Friday afternoon to determine which night the candidates will appear, a Democratic source tells Axios' Alexi McCammond.Go deeper: What you need to know about every 2020 candidate in under 500 words