Approximation Theory and Approximation PracticeThis textbook, with 163 figures and 210 exercises, was published in 2013. It is available from SIAM and from Amazon.Unusual features:

p 11: Exercise 2.2: in the final formula N should be n
p 22: Exercise 3.6: the exponent k1 should be (k1)/2
p 26: subscripts m should be n; k(mod 2n) should be (k)(mod 2n)
p 30: Exercise 4.4(d): length(f(np)) should be length(f(Mmax+1))
p 31: Exercise 4.6 should insert "(down to machine precision, in practice,
by Chebyshev interpolation)" before "and then"
p 47: Exercise 6.6(b): 2n should be 2n1 (6 times)
p 54: Exercise 7.6(b): s=linspace(1,1,10), p=chebfun(@(x) spline(s,exp(s),x));
p 57: just before the second displayed equation, (3.12) should be (3.13)
p 71: Exercise 9.8: sign(sin(x/2)) should be sign(x)
p 74: BolzanoWeierstrass should be HeineBorel
p 78: Exercise 10.1: after 'splitting','on' insert ,'minsamples',65
p 82: Cauchy stated a related formula but not exactly "the same result"
p 93: the product in (12.14) should run over j<k, not j≠k
p 119: the pointer to Exercise 10.5 should be to Exercise 10.6
p 127: the formulas need to be normalized by division by terms like (p_k,p_k)
pp 147, 151: Eqs. (19.10), (19.12) are incorrectly copied from
Trefethen (2008): (n2ν1)^{2ν+1} should be (2n+1ν)^ν
p 160: "maps [1,1]" should be "maps the unit circle"
p 166: Eq. (21.2) is incorrect (p. 166 and inside back cover)
p 215: the integral in (25.13) should have limits from ∞ to ∞
p 215: after (25.14), "even number" should be "odd number"
p 215: on the last line, type (n,n) should be type (n1,n)
p 222: in (26.3), r(z) should be r(x)
p 229: the summation at the bottom needs a square root
p 256: Lottka should be Lotka
p 296: de la Vallée Poussin (1910) is missing an annotation
p 300: Borel should also list page 75
p 304: Richardson extrapolation should list pages 257258
p 305: Weierstrass should not list page 75
OTHER NOTES:
p 151: concerning Xiang and Bornemann [2012], Bornemann has pointed out (personal communication, August 2013) that just the right result along these lines, derived from L^{1} approximation, appeared years ago as Theorem 2 in G. Freud, "Über einseitige Approximation durch Polynome. I," Act. Sci. Math. Szeged 16 (1955), 1228.