Across

• 1.

  TRY: TRY (1st, 4th, & 7th letters)
• 5.

  STRING: ST(R)ING
• 10.

  AUREATE: (l)AUREATE
• 11.

  RECUR: RE + CUR(e)
• 12.

  STELLA: S(TELL)A
• 13.

  FINITE: F(I + NIT)E ("tin I" rev.)
• 14.

  BURRS: BU(RR)S
• 16.

  SLATERS: S(LATER)S
• 18.

  LEGIT: LEG + IT
• 19.

  MENAD: MEN + AD
• 20.

  DERIVE: D(E)RIVE
• 25.

  SAGES: S(t)AGES
• 27.

  UNARM: UNARM (hidden)
• 28.

  DEN: (e)DEN
• 30.

  GENESIS: G + ENESIS ("g" + anag.)
• 33.

  SCALDS: SCA(L)DS
• 34.

  STEAL: S(T)EAL
• 35.

  ZING: Z+ IN + G
• 36.

  PENS: PENS (double def)
• 37.

  STEALTH: STEALTH (anag.)
• 38.

  SYSTEMS: S(all)Y + STEMS
• 39.

  CYST: C + Y + ST

Down

• 1.

  TASKS: T + ASKS
• 2.

  RUTHLESS: RUTHLESS
• 3.

  REGAN: REGAN (anag.)
• 4.

  VALUED: VAL(U)E + D
• 5.

  STARRED: S + TARRED
• 6.

  RILE: RI(f)LE
• 7.

  ICING: I + C + IN + G
• 8.

  NUTS: NUTS (rev.)
• 9.

  GREATER: GREATER (homophone)
• 15.

  SERENE: SER + ENE
• 17.

  TANGS: TANG + S (rev.)
• 21.

  VARIANTS: V + ARIA(NT)S
• 22.

  BBS: BB'S
• 23.

  CELTS: C(EL)TS
• 24.

  NASTILY: N(ASTI + L)Y
• 26.

  ENCASE: ENC(A)SE ("A" + anag.)
• 27.

  UNDER: UNDE + R (anag. + "r")
• 29.

  ESTES: ESTES (hidden)
• 31.

  SIGHT: SIGH + T
• 32.

  ESPY: ESP + Y