Here is a list of all documented files with brief descriptions:

A3	A3. Real arithmetic
C10a	C10a. Special functions (Bessel functions)
C10b	C10b. Special functions (Modified Bessel functions)
C14	C14. Special functions (Elliptic Integrals)
C19	C19. Special functions (other special functions)
C2	C2. Special functions (Powers, roots, reciprocals)
C4	C4. Special functions (Elementary transcendental functions)
C5	C5. Special functions (Exponential and logarithmic integrals)
C7a	C7a. Special functions (Gamma functions)
C7c	C7c. Special functions (Polygamma functions)
C8	C8. Special functions (Error functions)
D1b3	D1b. Elementary matrix operations (LAPACK auxiliary routines)
D2a	D2a. Solution of systems of linear equations (real nonsymmetric matrices)
D2b1b	D2b1b. Solution of systems of linear equations (real symmetric positive definite matrices)
D4a1	D4a1. Real symmetric matrix eigenvalue problems
D9a	D9a. Singular, overdetermined or underdetermined systems of linear equations without constraints
E	E. Interpolation
E3a3	E3a3. Quadrature involving fitted functions
F1a	F1a. Roots of polynomials
F1b	F1b. Solution of single general nonlinear equation
F2	F2. Solution of a system of nonlinear equations
G1a	G1a. Unconstrained optimization of a general univariate function
G1b	G1b. Unconstrained optimization of a general multivariate function
H2a1a	H2a1a. 1-D finite interval quadrature, integrand available via user-defined procedure
H2a3a	H2a3a. 1-D semi-infinite interval quadrature, integrand available via user-defined procedure
I1a1	I1a1. Nonstiff initial value problem for ordinary differential equations (ODEs)
J1a1	J1a1. One-dimensional real fast Fourier transforms
K1b1	K1b1. Unconstrained nonlinear least squares approximation
L6a21	L6a21. Uniform random numbers
R	R. Service routines